Process for the direct synthesis of Cu containing zeolites having CHA structure

ABSTRACT

A process for the preparation of a copper containing zeolitic material having CHA framework structure and a composition comprising the molar ratio (n YO2):X203 wherein X is a trivalent element, preferably Al, Y is a tetravalent element, preferably Si, and wherein n is preferably at least 20. The process comprising the preparation of an phosphor-free aqueous solution containing at least one source for X203 and at least one source for YO2, at least one structure directing agent suitable for the preparation of a zeolitic material having CHA framework structure, and at least one Cu source, and the process further comprising the hydrothermal crystallization of said aqueous solution obtaining a suspension containing the copper containing zeolitic material having CHA framework structure.

The present invention relates to a process for the preparation ofphosphor-free zeolitic materials having CHA framework structure andwhich contain Cu wherein said zeolitic material is obtained in a singleprocess stage. This process stage is a hydrothermal crystallizationstage to which an aqueous solution is subjected which, apart from tri-and/or tetravalent elements usually employed as framework elements ofthe zeolite framework, already contains all the Cu necessary for thepreparation of the final Cu zeolite having CHA framework structure. Inparticular, the present invention relates to such processes for thepreparation of zeolitic materials having CHA framework structure andexhibiting a high content of Cu wherein the obtained materialspreferably contain Si and Al and have a high molar ratio of Si:Al. Thepresent thus also relates to the zeolitic materials obtainable and/orobtained by this process as well as to specific zeolitic materials assuch which contain Cu and have CHA framework structure, and whichexhibit specific Si:Al ratios.

Zeolitic materials having chabazite (CHA) framework structure and whichcontain copper (Cu) are materials which are widely used in importantactual technical areas such as in the automotive industry where thematerials are employed as catalysts. Thus, these materials are of higheconomical and ecological interest. Due to the said technical areas andthe resulting need of high amounts of the materials, there is anincreasing demand for efficient processes for the preparation of thesematerials.

Molecular sieves are classified by the Structure Commission of theInternational Zeolite Association according to the rules of the IUPACCommission on Zeolite Nomenclature. According to this classification,framework-type zeolites and other crystalline microporous molecularsieves, for which a structure has been established, are assigned a threeletter code and are described in the Atlas of Zeolite Framework Types,5th edition, Elsevier, London, England (2001). Chabazite is one of themolecular sieves for which a structure has been established, and thematerial of this framework-type is designated as CHA.

U.S. Pat. No. 5,254,515 discloses crystalline silicates containingcopper. According to this document, the copper ions are applied to thecrystalline material by ion-exchange wherein ion-exchange sites such asalkali metal ions and hydrogen ions are replaced by copper ions viaimmersing the silicate in an aqueous solution in which a mineral acidsuch as copper sulphate, copper nitrate, or, e.g., copper acetate isdissolved.

U.S. Pat. No. 6,056,928 discloses catalysts for the removal of N₂O whichcan be beta zeolite, ZSM-5 zeolite, mordenite or chabazite. It isdisclosed that, likewise, catalysts are usable which are based onzeolite having been exchanged with Cu, Co, Rh, Pd or Ir, for example. Noexample is given for a Cu chabazite zeolite.

U.S. Pat. No. 7,067,108 B2 discloses zeolites of chabazite frameworktype. These zeolites are prepared by employing a specific seedingmaterial, namely a crystalline material having a framework type otherthan chabazite framework type, such as AEI type, LEV type, or OFF type.It is disclosed that any cations in the as-synthesized chabaziteframework-type material can be replaced at least in part by ion exchangewith other cations.

U.S. Pat. No. 6,974,889 B1 discloses a process for the manufacture of acrystalline molecular sieve, such as zeolites of structure type CHA orLEV, containing phosphorus in its framework, wherein a colloidalcrystalline molecular sieve is used as seed material. It is disclosedthat the synthesis mixture may contain a source of metallic elements,especially a Group VIII metal, more especially nickel. According toexamples, typical molar ratios of Al₂O₃:P₂O₅ in the zeolite frameworkare about 1:1. This metal is advantageously in a molar proportioncalculated as oxide relative to alumina within the range of 0.001 to0.05, preferably 0.005 to 0.01, i.e. in very low molar ratios metaloxide:alumina. According to U.S. Pat. No. 6,974,889 B1, other suitableGroup VIII metals include Fe and Co, while other suitable metals includeMn, Cr, Cu, Zn, Mg, Ti, and Zr. No example is given relating to a Cuzeolite, in particular Cu chabazite zeolite.

U.S. Pat. No. 4,996,322 relates to the separation of amides withmolecular sieves. According to this document, preferred zeolites forthis separation are zeolites of types A, X, Y, MFI and chabazite, andmordenite, calcium chabazite being particularly preferred. As to thechabazite zeolites, also Cu chabazite is disclosed. However, accordingto table 11 of U.S. Pat. No. 4,996,322, the copper chabazite is preparedby copper acetate exchange of a synthetic zeolite with a Si:Al ratio of2.1.

Therefore, it is an object of the present invention to provide a novelprocess for the preparation of phosphorus-free Cu containing zeoliticmaterials having CHA framework structure, in particular ofphosphorus-free containing zeolitic materials having CHA frameworkstructure having a high Cu content.

It is a further object of the present invention to provide a novelprocess for the preparation of phosphorus-free Cu containing zeoliticmaterials having CHA framework structure, in particular ofphosphorus-free containing zeolitic materials having CHA frameworkstructure having a high Cu content.

It is a further object of the present invention to provide a novel andefficient process for the preparation of phosphorus-free Cu containingzeolitic materials having CHA framework structure, wherein the zeoliticmaterial contains Si and Al in a high molar ratio of Si:Al and whereinthe zeolitic material exhibits, at the same time, a high Cu content.

It is a further object of the present invention to provide Cu containingzeolitic materials having CHA framework structure wherein the zeoliticmaterial exhibits a high Cu content, and preferably, also a high molarratio of Si:Al.

Therefore, the present invention relates to a process for thepreparation of a copper containing zeolitic material having CHAframework structure and a composition comprising the molar ratio(nYO₂):X₂O₃wherein X is a trivalent element, Y is a tetravalent element, andwherein n is preferably at least 10, more preferably at least 15, theprocess comprising

-   (i) preparation of an aqueous solution containing at least one    source for X₂O₃ and at least one source for YO₂, at least one    structure directing agent suitable for the preparation of a zeolitic    material having CHA framework structure, and at least one Cu source,    wherein said aqueous solution does not contain a phosphorus source;-   (ii) hydrothermal crystallization of the aqueous solution according    to (i) which does not contain a phosphor source, obtaining a    suspension containing the copper containing zeolitic material having    CHA framework structure.

The term “the aqueous solution does not contain a phosphorus source” asused in this context of the present invention relates to the fact thatno phosphorus containing compounds are used as such for the preparationfor the aqueous solution according to (i) which is subsequentlysubjected to hydrothermal crystallization. However, this term does notexclude such embodiments where the starting materials explicitlydescribed contain certain amounts of phosphorus or phosphorouscontaining compounds as impurities. By way of example, such impuritiesare typically present in amounts of below 1000 ppm, preferably below 500ppm, more preferably below 300 ppm.

X and Y

According to stage (i) of the present invention, all conceivable sourcesfor trivalent elements X and tetravalent elements Y may be employedwhich can build up the zeolitic framework and which, as part of thiszeolitic framework, are referred to as X₂O₃ and YO₂ in the context ofthe present invention.

Preferably, the trivalent element X is selected from the groupconsisting of Al, B, In, G, and a mixture of two or more thereof.

Generally, all suitable sources for B₂O₃ can be employed. By way ofexample, borates and/or boric acid, metaboric acid, ammonium metaborate,and/or boric acid esters such as boric acid triethyl ester or boric acidtrimethyl ester may be mentioned.

Generally, all suitable sources for In₂O₃ can be employed. By way ofexample, In nitrates may be mentioned.

Generally, all suitable sources for Ga₂O₃ can be employed. By way ofexample, Ga nitrates may be mentioned.

Generally, all suitable sources for Al₂O₃ can be employed. By way ofexample, metallic aluminum such as aluminum powder, suitable aluminatessuch as alkali metal aluminates, aluminum alcoholates such asaluminumtriisopropylate and aluminum hydroxide may be mentioned.According to a preferred embodiment of the present invention, however,an Al₂O₃ source is employed which is free of sodium, in particular freeof alkali metals. Aluminum hydroxide, Al(OH)₃, andaluminumtriisopropylate are especially preferred.

Therefore, the present invention relates to above-described processwherein the source for X₂O₃, in particular the source for Al₂O₃ is freeof sodium, in particular free of alkali metal.

According to an especially preferred embodiment of the presentinvention, the trivalent element X is Al, and even more preferably, noother trivalent element is used, Al thus being the only trivalentelement building up the CHA zeolitic framework structure.

Preferably, the tetravalent element Y is selected from group consistingof Si, Sn, Ti, Zr, Ge, and a mixture of two or more thereof.

Generally, all suitable sources for TiO₂ can be employed. By way ofexample, titanium oxide or titanium alcoholates such astetraethoxytitanate or tetrapropoxytitanate may be mentioned.

Generally, all suitable sources for SnO₂ can be employed. By way ofexample, tin chlorides or metalorganic tin compounds such as tinalcoholates or chelates such as tin-acetylacetonate may be mentioned.

Generally, all suitable sources for ZrO₂ can be employed. By way ofexample, zirconium chloride or zirconium alcoholates may be mentioned.

Generally, all suitable sources for GeO₂ can be employed. By way ofexample, germanium chloride may be mentioned.

Generally, all suitable sources for SiO₂ can be employed. By way ofexample, silicates, silica, silicic acid, colloidal silica, fumedsilica, tetraalkoxysilanes, silica hydroxides, precipitated silica orclays may be mentioned. In this context, both so-called “wet-processsilicon dioxide” as well as so called “dry-process silicon dioxide” canbe employed. Colloidal silicon dioxide is, inter alia, commerciallyavailable as Ludox®, Syton®, Nalco®, or Snowtex®. “Wet process” silicondioxide is, inter alia, commercially available as Hi-Sil®, Ultrasil®,Vulcasil®, Santocel®, Valron-Estersil®, Tokusil® or Nipsil®. “Dryprocess” silicon dioxide is commercially available, inter alia, asAerosil®, Reolosil®, Cab-O-Sil®, Fransil® or ArcSilica®.Tetraalkoxysilanes, such as, for example, tetraethoxysilane ortetrapropoxysilane, may be mentioned.

According to preferred embodiments of the present invention, dry-processsilica or colloidal silica is employed. If colloidal silica is employed,it is further preferred that said colloidal silica is stabilized withoutsodium, in particular without alkali metal. According to even morepreferred embodiments where colloidal silica is used, the colloidalsilica employed as aqueous solution in (i) is stabilized with ammonia.

Therefore, the present invention relates to above-described processwherein the source for YO₂, in particular the source for SiO₂ is free ofsodium, in particular free of alkali metal.

According to an especially preferred embodiment of the presentinvention, the tetravalent element Y is Si, and even more preferably, noother tetravalent element is used, Si thus being the only tetravalentelement building up the CHA zeolitic framework structure.

Consequently, according to an especially preferred embodiment of thepresent invention, X is Al and Y is Si, and even more preferably, noother trivalent and tetravalent element building up the zeoliticframework structure after hydrothermal crystallization is employed.

Therefore, the present invention relates to above-described processwherein X is selected from the group consisting of Al, B, In, G, and amixture of two or more thereof; and wherein Y is selected from the groupconsisting of Si, Sn, Ti, Zr, Ge, and a mixture of two or more thereof;X preferably being Al and Y preferably being Si.

Generally, the sources for X₂O₃ and YO₂ can be employed in allconceivable amounts and molar ratios for the preparation of the aqueoussolution in (i) with the proviso that in (ii), a Cu containing zeolitehaving CHA framework structure is obtained.

According to a preferred embodiment of the present invention, the atleast one source for YO₂ and the at least one source for X₂O₃ areemployed in such amounts that the aqueous solution obtained according to(i) exhibits a molar ratio(nYO₂):X₂O₃wherein n is at least 10, more preferably at least 15. More preferably,n is in the range of from 15 to 80, more preferably from 15 to 60, morepreferably from 15 to 50 such as, e.g., 15, 20, 25, 30, 35, 40, 45, 50.Cu Source

As far as the Cu source is concerned, all suitable compounds can beemployed for the preparation of the aqueous solution in (i) with theproviso that in (ii), a Cu containing zeolite having CHA frameworkstructure is obtained. Preferably, an aqueous solution of at least oneCu salt is employed. Preferred Cu salts are, e.g., CuCO₃, Cu acetate andCu(NO₃)₂.

Even more preferably, an aqueous solution of at least one suitable Cusalt is employed which, apart from water and the Cu salt, containsammonia.

Therefore, the present invention relates to above-described process,wherein an aqueous solution containing Cu and ammonia is employed as Cusource. According to a preferred embodiment, the amount of ammoniacontained in this aqueous solution is high enough so that the Cu whichis contained in the aqueous solution is present as [Cu(NH₃)₄]²⁺ complex.

Molar Ratios

Generally, the sources for X₂O₃ and YO₂ and Cu can be employed in allconceivable amounts and molar ratios for the preparation of the aqueoussolution in (i) with the proviso that in (ii), a Cu containing zeolitehaving CHA framework structure is obtained.

According to a preferred embodiment of the present invention, the atleast one source for YO₂ and the at least one source for X₂O₃ areemployed in such amounts that the aqueous solution obtained according to(i) exhibits a molar ratio of Cu relative to the sum of (n X₂O₃) andYO₂,(mCu):((nYO₂)+X₂O₃)wherein m is at least 0.005, more preferably at least 0.01, morepreferably at least 0.02. Even more preferably, said m is less than orequal to 0.08, more preferably less than or equal to 0.07, morepreferably less than or equal to 0.06, more preferably less than orequal to 0.05, and more preferably less than or equal to 0.04. Thus,according to preferred embodiments of the present invention, m is in therange of from 0.005 to 0.08, more preferably from 0.01 to 0.06, and evenmore preferably from 0.02 to 0.04.

Thus, the present invention also relates to above-described processwherein, for the preparation of the aqueous solution according to (i),the at least one source for YO₂, the at least one source for X₂O₃ andthe Cu source are employed in such amounts that the aqueous solutionobtained according to (i) exhibits a molar ratio(nYO₂):X₂O₃wherein n is at least 10, preferably at least 15, more preferably in therange of from 15 to 70, and a molar ratio(mCu):((nYO₂)+X₂O₃)wherein m is at least 0.005, preferably in the range of from 0.02 to0.04.

In particular, the present invention relates to above-described processwherein, for the preparation of the aqueous solution according to (i),the at least one source for SiO₂, the at least one source for Al₂O₃ andthe Cu source are employed in such amounts that the aqueous solutionobtained according to (i) exhibits a molar ratio(nSiO₂):Al₂O₃wherein n is in the range of from 15 to 50, and a molar ratio(mCu):((nSiO₂)+Al₂O₃)wherein m is in the range of from 0.02 to 0.04.Structure Directing Agent (SDA)

As far as the structure directing agent employed in (i) is concerned, norestriction exists with the proviso that a zeolitic material having CHAframework structure is obtained in (ii).

By way of example, a suitable N-alkyl-3-quinuclidinol, a suitableN,N,N-trialkyl-exoaminonorbornane, a suitableN,N,N-trimethyl-1-adamantylammonium compound, a suitableN,N,N-trimethyl-2-adamantylammonium compound, a suitableN,N,N-trimethylcyclohexylammonium compound, a suitableN,N-dimethyl-3,3-dimethylpiperidinium compound, a suitableN,N-methylethyl-3,3-dimethylpiperidinium compound, a suitableN,N-dimethyl-2-methylpiperidinium compound,1,3,3,6,6-pentamethyl-6-azonio-bicyclo(3.2.1)octane,N,N-dimethylcyclohexylamine, or a suitable N,N,N-trimethylbenzylammoniumcompound may be mentioned. As suitable compounds, the hydroxides ofabove-mentioned compounds may be mentioned.

Preferably, a suitable N,N,N-trimethyl-1-adamantylammonium(1-adamantyltrimethyl ammonium) compound is employed. Optionally, thissuitable 1-adamantyltrimethylammonium compound can be employed incombination with at least one further suitable ammonium compound suchas, e.g., a N,N,N-trimethylbenzylammonium (benzyltrimethylammonium)compound or a tetramethylammonium compound or a mixture of abenzyltrimethylammonium and a tetramethylammonium compound.

According to a preferred embodiment of the present invention, a mixtureof 1-adamantyltrimethylammonium compound and benzyltrimethylammoniumcompound is used wherein, even more preferably, the molar ratio ofbenzyltrimethylammonium compound to 1-adamantyltrimethylammonium ispreferably in the range of from 1:1 to 5:1, more preferably in the rangeof from 1.5:1 to 4:1 and even more preferably in the range of from 2:1to 3:1.

According to another preferred embodiment of the present invention, amixture of 1-adamantyltrimethyl ammonium compound andtetramethylammonium compound is used wherein, even more preferably, themolar ratio of tetramethylammonium compound to1-adamantyltrimethylammonium is preferably in the range of from 1:1 to5:1, more preferably in the range of from 1.1:1 to 4:1, more preferablyin the range of from 1.2 to 3:1 and even more preferably in the range offrom 1.3:1 to 2:1.

As far as the ammonium compounds are concerned, it is conceivable that asuitable salt of the ammonium compounds is employed. Preferably, if suchsalt is employed, this salt or the mixture of salts should impart thedesired pH to the aqueous solution to be subjected to hydrothermalcrystallization. If necessary, a suitable base such as, for example, asuitable hydroxide source, can be added, in addition said salt(s) toimpart said pH. Preferably, according to the present invention, theammonium salt or ammonium salts as such are the suitable base,preferably the hydroxide source, i.e., it is preferred that the ammoniumcompound(s) is/are employed as hydroxide(s).

Thus, preferred compounds used according to the present invention asstructure directing agent are 1-adamantyltrimethylammonium hydroxide,and benzyltrimethylammonium hydroxide and/or tetramethylammoniumhydroxide. Even more preferred is a mixture of these hydroxides.

According to a preferred embodiment, the molar ratio ofbenzyltrimethylammonium hydroxide to 1-adamantyltrimethylammoniumhydroxide is preferably in the range of from 1:1 to 5:1, more preferablyin the range of from 1.5:1 to 4:1 and even more preferably in the rangeof from 2:1 to 3:1.

According to another preferred embodiment, the molar ratio oftetramethylammonium hydroxide to 1-adamantyltrimethylammonium hydroxideis preferably in the range of from 1.1:1 to 4:1, more preferably in therange of from 1.2 to 3:1 and even more preferably in the range of from1.3:1 to 2:1.

Therefore, the present invention also relates to above-described processwherein the structure directing agent is a mixture of a1-adamantyltrimethylammonium compound and at least one further suitableammonium compound, preferably a mixture of 1-adamantyltrimethylammoniumhydroxide and benzyltrimethylammonium hydroxide or a mixture of1-adamantyltrimethylammonium hydroxide and tetramethylammonium hydroxideor a mixture of 1-adamantyltrimethylammonium hydroxide andbenzyltrimethylammonium hydroxide and tetramethylammonium hydroxide,wherein the molar ratio of 1-adamantyltrimethylammonium hydroxide tobenzyltrimethylammonium hydroxide or to tetramethylammonium hydroxide orto the sum of benzyltrimethylammonium hydroxide and tetramethylammoniumhydroxide is in the range of from 1:5 to 1:1.

Therefore, the present invention also relates to above-described processwherein the structure directing agent is a mixture of a1-adamantyltrimethylammonium compound and a benzyltrimethylammoniumcompound, preferably a mixture of 1-adamantyltrimethylammonium hydroxideand benzyltrimethylammonium hydroxide, wherein the molar ratio ofbenzyltrimethylammonium compound to 1-adamantyltrimethyl ammonium ispreferably in the range of from 2:1 to 3:1.

Therefore, the present invention also relates to above-described processwherein the structure directing agent is a mixture of a1-adamantyltrimethylammonium compound and a tetramethylammoniumcompound, preferably a mixture of 1-adamantyltrimethylammonium hydroxideand tetramethylammonium hydroxide, wherein the molar ratio oftetramethylammonium compound to 1-adamantyltrimethylammonium ispreferably in the range of from 1.3:1 to 2:1.

As far as the ammonium compounds are concerned, it also possibleaccording to the present invention to employ the respective aminecompound, if necessary in combination with at least one suitable basesuch as, e.g. a suitable hydroxide source

Generally, the sources for X₂O₃ and YO₂ and the structure directingagent can be employed in all conceivable amounts and molar ratios forthe preparation of the aqueous solution in (i) with the proviso that in(ii), a Cu containing zeolite having CHA framework structure isobtained.

According to a preferred embodiment of the present invention, the atleast one source for YO₂ and the at least one source for X₂O₃ areemployed in such amounts that the aqueous solution obtained according to(i) exhibits a molar ratio of structure directing agent (SDA) relativeto the sum of (n X₂O₃) and YO₂,(pSDA):((nYO₂)+X₂O₃)wherein p is at least 0.035, more preferably at least 0.07, morepreferably at least 0.15. Even more preferably, p is less than or equalto 0.6, more preferably less than or equal to 0.5, more preferably lessthan or equal to 0.4, more preferably less than or equal to 0.3, andmore preferably less than or equal to 0.2. Thus, according to preferredembodiments of the present invention, p is in the range of from 0.035 to0.6, more preferably from 0.07 to 0.4, and even more preferably from0.15 to 0.2.

Thus, the present invention also relates to above-described processwherein, for the preparation of the aqueous solution according to (i),the at least one source for YO₂, the at least one source for X₂O₃ andthe SDA source are employed in such amounts that the aqueous solutionobtained according to (i) exhibits a molar ratio(nYO₂):X₂O₃wherein n is at least 10, preferably at least 15, preferably in therange of from 15 to 70, and a molar ratio(pSDA):((nYO₂)+X₂O₃)wherein p is at least 0.035, preferably in the range of from 0.15 to0.2.The pH of the Aqueous Solution

Preferably, the pH of the aqueous solution obtained from (i) andsubjected to hydrothermal crystallization according to (ii) is at least10, more preferably at least 11, and even more preferably at least 12.More preferably, the pH of the aqueous solution subjected tohydrothermal crystallization according to (ii) is in the range of from12 to 14.

Thus, the present invention also relates above-described process,wherein the pH of the aqueous solution subjected to (ii) is in the rangeof from 12 to 14.

Depending on the starting materials employed, it may be necessary toadjust the pH of the aqueous solution subjected to hydrothermalcrystallization according to (ii) so that the pH has above-describedvalues. Preferably, adjusting the pH is carried out using a base whichdoes not contain sodium, preferably a base which does not contain analkali metal, such as, e.g., sodium hydroxide or the like.

Preferably, the pH is adjusted to above-described values using ammoniawhich may be added as aqueous solution, e.g. as aqueous solutioncontaining the at least one Cu salt described above.

Also preferably, the pH is adjusted to above-described values usingsuitable structure directing compounds, for example the respectiveammonium hydroxide compounds as described above. In particular, in casea mixture of 1-adamantyltrimethylammonium hydroxide andtetramethylammonium hydroxide is used, tetramethylammonium hydroxideprimarily acts as a source of hydroxide and thus, as a suitable base foradjusting the pH to above-described values.

Accordingly, the present invention also relates to the use oftetramethylammonium hydroxide as basic compound for adjusting the pH ofa solution to be subjected to hydrothermal crystallization of a Cucontaining zeolitic material having CHA structure, in particular foradjusting the pH to a value in the range of from 12 to 14.

Alkali Metal Content

As already described above, the at least one source for YO₂, preferablySiO₂, and the at least one source for X₂O₃, preferably Al₂O₂, are freeof sodium, in particular free of alkali metal. According to an even morepreferred embodiment of the present invention, the aqueous solutionobtained in (i) and subjected to hydrothermal crystallization in (ii) isfree of sodium, in particular free of alkali metal. Thus, for example,adjusting to pH of the aqueous solution subjected to hydrothermalcrystallization according to (ii)—if necessary—is preferably carried outusing bases which are free of sodium, in particular free of alkalimetal; adjusting the pH is preferably carried out via the aqueoussolution containing the at least one Cu salt described above,containing, as basic material, preferably ammonia.

The term “free of alkali metal” and “free of sodium”, as used in thiscontext of the present invention relates to the fact that no startingmaterials are employed which contain sodium, in particular alkali metalas essential component, such as, e.g., sodium aluminate as source forAl₂O₂, or the like. However, this term does not exclude such embodimentswhere the starting materials explicitly described contain certainamounts of sodium, in particular alkali metals as impurities. By way ofexample, such impurities are typically present in amounts of 1000 ppm orless, preferably 500 ppm or less, more preferably 300 ppm or less.

Therefore, the present invention also relates to above-describedprocess, wherein the aqueous solution subjected to hydrothermalcrystallization according to (ii) is free of sodium, in particular freeof alkali metal.

Accordingly, the present invention also relates to a zeolitic materialobtained and/or obtainable from the inventive process, having chabaziteframework structure, and being free of sodium, in particular free ofalkali metal.

In particular, in accordance with above-described definition, thepresent invention also relates to a zeolitic material obtained and/orobtainable from the inventive process, having chabazite frameworkstructure, having a sodium content, in particular an alkali metalcontent of 1000 ppm or less, preferably 500 ppm or less, more preferablyof 300 ppm or less.

The term “an alkali metal content of X ppm or less” as used in thecontext of the present, relates to an embodiment according to which thesum of all alkali metals present does not exceed X ppm.

Other Conceivable Starting Materials

According to further embodiments, the aqueous solution subjected to (ii)may contain at least one further metal, such as, for example, transitionmetals and/or lanthanides.

According to the embodiment according to which the aqueous solution maycontain a transition metal, the at least one further metal is preferablyselected from the group consisting of Fe, Co, Ni, Zn, Y, and V.Generally, all suitable Fe sources can be employed. By way of example,nitrate, oxalate, sulphate may be mentioned. Generally, all suitable Cosources can be employed. By way of example, nitrate, oxalate, sulphatemay be mentioned. Generally, all suitable Ni sources can be employed. Byway of example, nickel oxide, nickel salts such as nickel chloride,nickel bromide, nickel iodide and its hydrate, nickel nitrate and itshydrates, nickel sulfate and its hydrates, nickel acetate and itshydrates, nickel oxalate and its hydrates, nickel carbonate, nickelhydroxide, or nickel acetylacetonate may be mentioned. Generally, allsuitable Zn sources can be employed. By way of example, oxalate, acetatemay be mentioned. Generally, all suitable V sources can be employed. Byway of example, suitable vanadyle salts may be mentioned.

Therefore, the present invention also describes a process wherein theaqueous solution subjected to (ii) contains at least one further metalsource, said further metal being selected from the group consisting ofFe, Co, Ni, Zn, Y, and V.

According to a particularly preferred embodiment, the present inventionrelates to above-described process wherein the aqueous solutionsubjected to (ii) contains at least one Si source, at least one Alsource, and at least one Cu source, and contains no other source for XO₂and Y₂O₃, and contains no further metal such as Fe, Co, Ni, Zn, Y, or V,in particular no transition metal.

According to a further embodiment of the present invention, the aqueoussolution subjected to (ii) contains a suitable lanthanide source, suchas a suitable cerium source or a suitable lanthanum source, preferably asuitable La (lanthanum) source. While all suitable La sources areconceivable, a preferred La source, e.g., is a La salt which is solublein the aqueous solution. A preferred La source is, among others,lanthanum nitrate. Still more preferably, as far as the overall processfor producing the Cu containing zeolitic material is concerned, thelanthanum source is only employed in the aqueous solution subjected to(ii). In particular, neither the dried nor the calcined zeoliticmaterial is subjected to any treatments wherein a La source is employed.

Generally, the La source can be employed in such amounts that thefinally obtained material has the desired La content. Preferably, theaqueous solution subjected to (ii) has an atomic ratio of La:Cu in therange of from 1:10 to 1:100.

According to a particularly preferred embodiment, the present inventionrelates to above-described process wherein the aqueous solutionsubjected to (ii) contains at least one Si source, at least one Alsource, at least one Cu source, and at least one La source, and containsno other source for XO₂ and Y₂O₃, and contains no further metal such asFe, Co, Ni, Zn, Y, or V, in particular no transition metal.

Therefore, the present invention also relates to the process asdescribed above, wherein the aqueous solution subjected to hydrothermalcrystallization according to (ii) contains a La source, preferably insuch an amount that the atomic ratio La:Cu is in the range of from 1:10to 1:100, more preferably in the range of from 1:20 to 1:80, even morepreferably in the range of from 1:30 to 1:60.

Preparation of the Aqueous Solution According to (i)

Generally, there are no specific restrictions in which order thestarting materials are mixed to obtain the aqueous solution according to(i).

According to one embodiment of the present invention, an aqueoussolution containing the at least one structure directing agent is mixedwith an aqueous solution containing the Cu source, and, preferably,additionally ammonia, as described above. In this solution, the at leastone source for X₂O₃, preferably Al₂O₃, and the at least one source forYO₂, preferably SiO₂, suspended.

According to another embodiment of the present invention, an aqueoussolution containing the at least one source for X₂O₃, preferably Al₂O₃,is admixed with the at least structure directing agent, wherein,subsequently, the at least one source of Cu is added, and finally, theat least one source for YO₂, preferably SiO₂, is added.

According to a preferred embodiment of the present invention, the atleast one source for YO₂ and the at least one source for X₂O₃ areemployed in such amounts that the aqueous solution obtained according to(i) exhibits a molar ratio of water relative to the sum of (n X₂O₃) andYO₂,(qH₂O):((nYO₂)+X₂O₃)wherein q is at least 10, more preferably at least 15 and even morepreferably at least 20. Even more preferably, said q is less than orequal to 70, more preferably less than or equal to 65, more preferablyless than or equal to 60, more preferably less than or equal to 55, andmore preferably less than or equal to 50. Thus, according to preferredembodiments of the present invention, q is in the range of from 10 to70, more preferably from 15 to 60, and even more preferably from 20 to50.

Thus, the present invention also relates to above-described processwherein, for the preparation of the aqueous solution according to (i),the at least one source for YO₂, the at least one source for X₂O₃ andwater are employed in such amounts that the aqueous solution obtainedaccording to (i) exhibits a molar ratio(nYO₂):X₂O₃wherein n is at least 10, preferably at least 17, preferably in therange of from 15 to 70, and a molar ratio(qH₂O):((nYO₂)+X₂O₃)wherein q is at least 10, preferably in the range of from 20 to 50.

Hence, the present invention also relates to above-described processwherein, for the preparation of the aqueous solution according to (i),the at least one source for YO₂, preferably SiO₂, more preferablyexclusively SiO₂, the at least one source for X₂O₃, preferably Al₂O₃,more preferably exclusively Al₂O₃, and Cu source, SDA, and water areemployed in such amounts that the aqueous solution obtained according to(i) exhibits a molar ratio(nYO₂):X₂O₃wherein n is at least 10, preferably is at least 15, preferably in therange of from 15 to 70, a molar ratio(mCu):((nYO₂)+X₂O₃)wherein m is at least 0.005, preferably in the range of from 0.02 to0.04, a molar ratio(qH₂O):((nYO₂)+X₂O₃)wherein q is at least 10, preferably in the range of from 20 to 50, anda molar ratio(pSDA):((nYO₂)+X₂O₃)wherein p is at least 0.035, preferably in the range of from 0.15 to0.2.

The temperature during the preparation of the aqueous solution accordingto (i) is preferably in the range of from 10 to 40° C., more preferablyin the range of from 15 to 35° C., and particularly preferably in therange of from 20 to 30° C.

If, for the purpose of preparing the aqueous solution according to (i),higher amounts of water as described above shall be used, it isconceivable to suitably adjust the water content of the aqueous solutionto be in above-described preferred ranges. According to a suitablemethod preferred among others, the water content can be adjusted byremoving water in at least one suitable apparatus. According to thisembodiment, the water can be removed at a temperature in the range of,preferably, from 60 to 85° C., more preferably of from 65 to 80° C. andparticularly preferably of from 65 to 75° C. Accordingly, the presentinvention also relates to a process as described above, wherein,according to (i), an aqueous solution is prepared, and, prior to (ii),the water content of the aqueous solution obtained according to (i) isadjusted so that the aqueous solution exhibits a molar ratio of waterrelative to the sum of (n X₂O₃) and YO₂,(qH₂O):((nYO₂)+X₂O₃)wherein q is at least 10, more preferably at least 15, more preferablyat least 20. Even more preferably, q is less than or equal to 70, morepreferably less than or equal to 65, more preferably less than or equalto 60, more preferably less than or equal to 55, and more preferablyless than or equal to 50. Thus, according to preferred embodiments ofthe present invention, q is in the range of from 10 to 70, morepreferably from 15 to 60, and even more preferably from 20 to 50. Interalia, rotary evaporators or ovens may be mentioned as at least onesuitable apparatus. An oven is particularly preferred. Inter alia,apparatus which permit removal of water at reduced pressure and hence atlow temperatures, such as, for example, rotary evaporators operatedunder reduced pressure, may be mentioned.Hydrothermal Crystallization

In principle, it is possible to heat the aqueous solution according to(ii) under any suitable pressure and any suitable temperature ortemperatures, provided that it is ensured that zeolitic material of CHAframework structure crystallizes in the solution. Here, temperatureswhich, at the chosen pressure, are above the boiling point of thesolution obtained according to (i) are preferred. Temperatures of up to200° C. at atmospheric pressure are more preferred. The term“atmospheric pressure” as used in the context of the present inventiondesignates a pressure of, ideally, 101 325 Pa, which, however, may besubject to variations within the limits known to the person skilled inthe art. For example, the pressure may be in the range of from 95 000 to106 000 or of from 96 000 to 105 000 or of from 97 000 to 104 000 or offrom 98 000 to 103 000 or of from 99 000 to 102 000 Pa.

According to a particularly preferred embodiment of the processaccording to the invention, the hydrothermal crystallization accordingto (ii) is carried out in an autoclave.

The present invention accordingly also relates to a process as describedabove, wherein the hydrothermal crystallization in (ii) is carried outin an autoclave.

The temperature used in the autoclave according to (ii) is preferably inthe range of from 100 to 200° C., more preferably in the range of from120 to 195° C., more preferably in the range of from 130 to 190° C.,more preferably in the range of from 140 to 185° C. and particularlypreferably in the range of from 150 to 180° C.

Accordingly, the present invention also relates to a process asdescribed above, wherein the aqueous solution obtained according to (i),optionally after concentration as described above, is heated to atemperature in the range of from 100 to 200° C. according to (ii) in anautoclave.

According to an even more preferred embodiment of the present invention,the autoclave employed for carrying out the hydrothermal crystallizationaccording to (ii) exhibits means for heating and cooling the content ofthe autoclave, more preferably external heating means such as a suitableheating/cooling jacket.

Heating the aqueous solution to said temperatures can be carried outcontinuously; discontinuously, such as stepwise; or semi-continuously,such as continuously up to a first temperature, holding the solution atthis temperature for a given period of time, and further heating thesolution from the first temperature to the desired final temperature, asdescribed above. Also two or more temperature plateaus are conceivable.Preferably, the aqueous solution is heated continuously with atemperature profile in the range of from 5 to 95° C./h, more preferablyfrom 10 to 55° C./h, and even more preferably 15 to 25° C./h.

Moreover, the present invention also relates to a process as describedabove, wherein the hydrothermal crystallization according to (ii) iscarried out at a temperature in the range of from 100 to 200° C.

This temperature to which the aqueous solution is heated according to(ii) can in principle be maintained until the crystallization has takenplace to the desired extent. Here, time periods of up to 340 h, morepreferably of up to 300 h, more preferably of 260 h, more preferablyfrom 1 h to 260 h, more preferably from 2 h to 252 h, more preferablyfrom 3 to 252 h, more preferably from 4 to 240 h, more preferably from 5to 216 h, more preferably from 6 to 192 h, more preferably from 8 to 168h, more preferably from 12 to 144 h, more preferably from 24 to 120 h,more preferably from 48 to 115 h and more preferably from 50 to 110 hare preferred.

Therefore, the present invention also relates to a process as describedabove, wherein the hydrothermal crystallization according to (ii) iscarried out at for a time period of from 12 to 144 h, preferably from 24to 120 h, preferably from 48 to 115 h, and more preferably from 50 to110 h.

According to further preferred embodiments of the present invention,crystallization times are in the range of from 12 to 48 h, morepreferably from 24 to 48 h. Therefore, the present invention alsorelates to a process as described above, wherein the hydrothermalcrystallization according to (ii) is carried out at for a time period offrom 12 to 48 h, more preferably from 24 to 48.

During crystallization, pressure or pressures in the range of from 1 to20 bar, more preferably from 2 to 10 bar and even more preferably from 5to 8 bar are especially preferred.

Accordingly, the present invention also relates to a process asdescribed above, wherein the colloidal solution obtained according to(i), optionally after concentration as described above, is heated for atime period in the range of from 12 to 144 h, preferably from 24 to 120h, preferably from 48 to 115 h, and more preferably from 50 to 110 haccording to (ii) at a pressure or at pressures in the range of from 1to 20 bar, more preferably from 2 to 10 bar and even more preferablyfrom 5 to 8 bar.

Thus, the present invention also relates to a process as describedabove, wherein the colloidal solution obtained according to (i),optionally after concentration as described above, is heated for a timeperiod in the range of from 12 to 48 h, preferably from 24 to 48 h,according to (ii) at a pressure or at pressures in the range of from 1to 20 bar, more preferably from 2 to 10 bar and even more preferablyfrom 5 to 8 bar.

The aqueous solution is preferably suitably stirred for thecrystallization according to (ii). It is also possible to rotate thereaction vessel in which the crystallization is carried out. Typicalvalues as far as said stirring or rotation is concerned are in the rangeof from 40 to 250 rpm such as from 50 to 250 rpm (revolutions perminute).

While it is possible in the context of the present invention to addsuitable seeding material to the solution subjected to stage (ii), suchas optionally dried and/or calcined zeolitic material having CHAframework structure, it is preferred to carry out the hydrothermalcrystallization and in particular the whole inventive process withoutseeding material.

Therefore, the present invention relates to above-described processwherein no seeding material is added, in particular no seeding materialis added to the solution subjected to hydrothermal crystallizationaccording to (ii).

According to another embodiment of the present invention, it was foundthat using a suitable seeding material during hydrothermal synthesis maybe advantageous, in particular with regard to crystallinity of theobtained chabazite material and the hydrothermal crystallization time.While there are no particular restrictions as to the seeding materialwith the proviso that the desired chabazite material is obtained, it ispreferred that chabazite zeolite is employed as seeding material.Further, it is conceivable that it may be possible to employ, as seedingmaterial, as-synthesized chabazite zeolite, dried chabazite zeolite suchas, for example, spray-dried and non-calcined chabazite zeolite, or(optionally dried) calcined chabazite zeolite. Further, it isconceivable that employing from 0.1 to 10 wt.-% seeding material, basedon Si contained in the synthesis mixture, calculated as SiO₂, may beadvantageous. Exemplary amounts of seeding material, based on Si in thesynthesis mixture, are, for example, 1 to 9 wt.-%, 2 to 8 wt.-%, 3 to 7wt.-%, or 4 to 6 wt.-%.

Therefore, the present invention also relates to above-described processwherein a seeding material is added, in particular a seeding material isadded to the solution subjected to hydrothermal crystallizationaccording to (ii).

According to one embodiment of the process according to the invention,the crystallization according to (ii) can be terminated by suitablequenching. Here, it is particularly preferred to add water to thesuspension, wherein the water has a temperature which is suitable forterminating the crystallization.

According to another embodiment of the present invention, thecrystallization according to (ii) is terminated without quenching,preferably by terminating supply of heat to the autoclave, morepreferably by terminating supply of heat to the autoclave via the jacketof the autoclave. Terminating the supply of heat can be carried out byeither terminating supply of heating medium to the jacket or byterminating supply of heating medium and passing at least one suitablecooling medium through the jacket.

After hydrothermal crystallization according to (ii), the mother liquorcontaining the inventive Cu containing zeolitic material having CHAframework structure is suitably separated from said mother liquor. Priorto separation, the temperature of the mother liquor containing thezeolitic material may be suitably decreased to a desired value employinga suitable cooling rate. Typical cooling rates are in the range of from15 to 45° C./h, preferably from 20 to 40° C./h, and even more preferablyfrom 25 to 35° C./h.

Typical temperatures of the cooled mother liquor containing theinventive Cu containing zeolitic material having CHA framework structureare in the range of from 25 to 55° C., preferably of from 35 to 50° C.

Separation and Drying Stages

According to one embodiment of the process according to the invention,the Cu containing zeolitic material having CHA framework structure isseparated in a suitable manner in at least one step from the suspension,i.e. the mother liquor containing the zeolitic material, obtained from(ii). This separation can be effected by all suitable methods known tothe skilled person, for example, by decantation, filtration,ultrafiltration, diafiltration or centrifugation methods or, forexample, spray drying and spray granulation methods.

The suspension obtained according to (ii) as such or the suspensionobtained by concentrating the suspension obtained according to (ii) canbe subjected to the separation, for example separation by spray methods.Concentrating the suspension obtained according to (ii) can be achieved,for example, by evaporating, as for example evaporating under reducedpressure, or by cross flow filtration. Likewise, the suspension obtainedaccording to (ii) can be concentrated by separating the suspensionaccording to (ii) into two fractions wherein the solid contained in oneof both fractions is separated off by filtration, ultrafiltration,diafiltration, or centrifugation or spray methods and is suspended afteran optional washing step and/or drying step in the other fraction of thesuspension. The sprayed material, obtained by spray drying and spraygranulation drying, such as fluidized-bed spray granulation drying, ascombined separation and drying methods, can contain solid and/or hollowspheres, and can substantially consist of such spheres, respectively,which have, for example, a diameter in the range of from 5 to 500 μm oralso 5 to 300 μm. Single component or multiple component nozzles can beused during spraying as spray nozzles. The use of a rotary atomizer isalso conceivable. Possible inlet temperatures for the used carrier gasare, for example, in the range of from 200 to 600° C., preferably in therange of from 225 to 550° C., and more preferably in the range of from300 to 500° C. The outlet temperature of the carrier gas is, forexample, in the range of from 50 to 200° C. Air, lean air oroxygen-nitrogen mixtures with an oxygen content of up to 10 vol. %,preferably of up to 5 vol. %, more preferably of less than 5 vol. %, as,for example, of up to 2 vol. %, may be mentioned as carrier gases. Thespray methods can be carried out in counter-current or co-current flow.

Therefore, the present invention also relates to above-describedprocess, additionally comprising

-   (iii) separating the Cu containing zeolitic material from the    suspension obtained according to (ii).

Depending on the structure directing agent content of the mother liquorseparated from the zeolitic material, the structure directing agent canbe re-used in (i), optionally after having been suitably separated fromthe mother liquor. According to an alternative, the mother liquorcontaining structure directing agent can be re-used as such in (i),without separation of the structure directing agent.

If, e.g., the zeolitic material is separated by filtration orcentrifugation or concentration of the suspension obtained according to(ii), it is preferred that that the separated zeolitic material issuitably dried. Before the separated zeolitic material is dried, it maybe washed at least once with a suitable washing agent, wherein it ispossible to use identical or different washing agents or mixtures ofwashing agents in the case of at least two of the washing steps and touse identical or different drying temperatures in the case of at leasttwo drying steps.

The drying temperatures here are preferably in the range of from roomtemperature to 200° C., more preferably of from 60 to 180° C., morepreferably of from 80 to 160° C. and more preferably in the range offrom 100 to 150° C.

The durations of drying are preferably in the range of from 2 to 48 h,more preferably of from 4 to 36 h.

Accordingly, the present invention also relates to the process asdescribed above, additionally comprising drying the Cu containingzeolitic material, separated according to (iii), at a temperature in therange of from 100 to 150° C.

Moreover, the present invention also relates to the process as describedabove, additionally comprising

-   (iii) separating the Cu containing zeolitic material from the    suspension obtained according to (ii);-   (iv) drying the Cu containing zeolitic material, separated according    to (iii), at a temperature in the range of from 100 to 150° C.

Washing agents used may be, for example, water, alcohols, such as, forexample, methanol, ethanol or propanol, or mixtures of two or morethereof. For example, mixtures of two or more alcohols, such as, forexample, methanol and ethanol or methanol and propanol or ethanol andpropanol or methanol and ethanol and propanol, or mixtures of water andat least one alcohol, such as, for example, water and methanol or waterand ethanol or water and propanol or water and methanol and ethanol orwater and methanol and propanol or water and ethanol and propanol orwater and methanol and ethanol and propanol, may be mentioned asmixtures. Water or a mixture of water and at least one alcohol,preferably water and ethanol, is preferred, wherein water as the solewashing agent being is very particularly preferred.

If, e.g., the separation is carried out by means of spray drying methodsor spray granulation methods, as described above, this method providesthe advantage that the separation of the zeolitic material from thesuspension obtained according to (ii) and the drying of the zeoliticmaterial can be carried out in a single step.

Additionally, in particular where the separation is carried out by meansof spray drying methods or spray granulation methods, suitable compoundsmay be added to the suspension which is subjected to the spray dryingmethods or spray granulation methods. Such compounds can be pore formingagents resulting in, e.g., micropores and/or mesopores, bindercompounds, or the like. In general, suitable binders are all compoundswhich impart adhesion and/or cohesion between the zeolitic materialparticles to be bonded which goes beyond the physisorption which may bepresent without a binder. Examples of such binders are metal oxides,such as, for example, SiO₂, Al₂O₃, TiO₂, ZrO₂ or MgO or clays, ormixtures of two or more of these compounds.

Therefore, the following preferred separation, washing and or dryingsequences may be listed by way of example in the context of the presentinvention:

-   (a) The mother liquor containing the Cu containing zeolitic material    having CHA framework type is subjected to spraying without further    treatment, i.e. it is subjected to spraying as obtained from    hydrothermal crystallization, optionally after suitable cooling.    Prior to spraying, the suspension can be admixed with suitable    compounds such as pore forming agents or binder compounds.-   (b) The mother liquor containing the Cu containing zeolitic material    having CHA framework type is subjected to spraying after suitable    concentration, as described above. Prior to spraying, the suspension    can be admixed with suitable compounds such as pore forming agents    or binder compounds.-   (c) The mother liquor containing the Cu containing zeolitic material    having CHA framework type is subjected to a separation stage    different from spraying, e.g. to decantation, filtration,    ultrafiltration, diafiltration or centrifugation.

The sprayed material obtained from (a) or (b) or the material obtainedfrom (c) can be washed at least once, with at least one suitable washingagent, optionally admixed with at least one suitable base and/or atleast one suitable acid. After the washing stage or the washing stages,the material can be suitably dried wherein the drying temperatures arepreferably in the range of from room temperature to 200° C., morepreferably of from 60 to 180° C., more preferably of from 80 to 160° C.,and more preferably in the range of from 100 to 150° C., the durationsof drying preferably being in the range of from 2 to 48 h, morepreferably of from 4 to 36 h.

If the material is obtained according to (c), the optionally washed andoptionally dried material can be slurried in at least one suitablecompound such as, e.g. water. The suspension thus obtained may besubjected to a spraying stage such as spray drying or spray granulationdrying. Prior to spraying, at least one suitable further compound suchas a pore forming agent and/or a binder compound may be added to thesuspension. After this spraying stage, the sprayed material may besubjected to at least one suitable washing stage, optionally followed bya subsequent suitable drying stage.

If the zeolitic material according to the present invention is separatedfrom its mother liquor by filtration, it is particularly preferred toadmix a suitable amount of a suitable acidic compound to the suspensioncontaining the zeolitic material prior to filtration. Most preferably,such amounts of acidic compounds are added that the pH of the resultingsuspension to be filtrated is in the range of from 6 to 8, preferably inthe range of from 6.5 to 7.5 and more preferably in the range of from6.8 to 7.2 such about 6.5, 6.6, 6.7, 6.8, 6.9, 7.0, 7.1 or 7.2 or 7.3 or7.4 or 7.5. Surprisingly, it has been found that adjusting the pH of thesuspension to such values, in particular to values around 7.0 stronglyfacilitates aggregation of the zeolitic crystalline material containedin the suspension and, thus, strongly facilitates formation of arespective filter cake and, in turn, the separation of the zeoliticmaterial from its mother liquor. Such acids are preferred which can beeasily removed via drying and calcination, as described herein. Amongothers, nitric acid or suitable organic acids such as formic acid oracetic acid may be mentioned as suitable acid.

Calcination

According to a particularly preferred embodiment of the processaccording to the invention, the zeolitic material obtained according to(iii) or (iv), preferably after (iv), is calcined in at least oneadditional step.

Therefore, the present invention also relates to above-describedprocess, additionally comprising calcining the Cu containing zeoliticmaterial.

It is possible in principle to feed the suspension comprising thezeolitic material directly to the calcination. Preferably, the zeoliticmaterial is separated from the suspension, as described above, accordingto (iii), before the calcination. Even more preferably, the zeoliticmaterial is dried before the calcination.

The calcination of the zeolitic material obtained according to (ii)and/or (iii) and/or (iv) is preferably effected at a temperature in therange of up to 750° C. According to one alternative, if the calcinationis carried out under static conditions, such as, e.g., in a mufflefurnace, temperatures of up to 600 to 650° C. are preferred. Accordingto another alternative, if the calcination is carried out under dynamicconditions, such as, e.g., in a rotary calciner, temperatures of up to700 to 750° C. are preferred.

According to a preferred embodiment of the process according to theinvention, the zeolitic material is heated thereby from room temperatureor from the temperature employed for the drying stage to a temperatureof up to 750° C., wherein, more preferably, the heating rate is in therange of from 0.1 to 10° C./min, more preferably of from 0.2 to 5°C./min and particularly preferably in the range of from 1 to 4° C./min.This temperature is preferably, for example, in the range of from 200 to750° C. Calcination temperatures in the range of from 250 to 700° C. arepreferred, temperatures in the range of from 300° C. to 650° C. areparticularly preferred.

According to an especially preferred embodiment of the presentinvention, calcination is carried out for such a period of time that thetotal organic carbon (TOC) content of the resulting calcined material is0.1 wt.-% or less, based on the total weight of the calcined material.

Therefore, the present invention also relates to above-describedprocess, additionally comprising

-   (v) calcining the Cu containing zeolitic material, preferably dried    according to (iv), at a temperature in the range of from 300 to 650°    C.,    wherein, according to an even more preferred embodiment, the heating    rate for achieving this temperature is in the range of from 0.1 to    10° C./min, in particular in the range of from 1 to 4° C./min.

According to a possible embodiment of the process according to theinvention, the calcination is carried out stepwise at successivetemperatures. The term “stepwise at successive temperatures” as used inthe context of the present invention designates a calcination in whichthe zeolitic material to be calcined is heated to a certain temperature,kept at this temperature for a certain time and heated from thistemperature to at least one further temperature and kept there in turnfor a certain time. Preferably, the zeolitic material to be calcined iskept at up to 4 temperatures, more preferably at up to 3 temperaturesand particularly preferably at 2 temperatures. In this respect, thefirst temperature is preferably in the range of from 300 to 550° C.,more preferably in the range of from 350 to 550° C. This temperature ispreferably maintained for a time in the range of from 1 to 24 h, morepreferably of from 2 to 18 h and in particular of from 5 to 10 hours.The second temperature is preferably in the range of from greater than550 to 750° C., more preferably in the range of from 575 to 700° C. andparticularly preferably in the range of from 600 to 650° C. Thistemperature is preferably maintained for a time in the range of from 1to 24 h, more preferably of from 2 to 18 h and in particular of from 5to 10 hours.

Accordingly, the present invention also relates to a process asdescribed above, wherein the calcination is effected stepwise atsuccessive temperatures in the range of up to 750° C., preferably from200 to 750° C., more preferably from 250 to 700° C., more preferablyfrom 300 to 650° C.

If the calcination is carried out stepwise, the respective heating ratesto achieve the desired temperatures may be the same or different. If,e.g., calcination is carried out at two temperatures, the firsttemperature preferably being in the range of from 300 to 550° C., morepreferably in the range of from 350 to 550° C., this temperaturepreferably being maintained for a period of time in the range of from 1to 24 h, more preferably of from 2 to 18 h and in particular of from 5to 10 hours, preferred heating rates to achieve this temperature are inthe range of from 0.1 to 10° C./min, more preferably of from 1 to 4°C./min. The heating rate for achieving the second temperature,preferably being in the range of from greater than 550 to 750° C., morepreferably in the range of from 600 to 650° C., this temperaturepreferably being maintained for a time in the range of from 1 to 24 h,more preferably of from 2 to 18 h and in particular of from 5 to 10hours, is preferably in the range of from 0.1 to 10° C./min, morepreferably of from 1 to 4° C./min.

According to a preferred embodiment of the present invention, the firstheating rate to achieve the first temperature may be in the range offrom 1.5 to 2.5° C./min, more preferably of from 1.75 to 2.25° C./min,and the second heating rate to achieve the second temperature may be inthe range of from 0.5 to 1.5° C./min, more preferably of from 0.75 to1.25° C./min.

Therefore, the present invention also relates to above-describedprocess, additionally comprising

-   (v)(a) calcining the Cu containing zeolitic material, preferably    dried according to (iv), at a first temperature in the range of from    300 to 550° C., more preferably in the range of from 350 to 550° C.,    wherein, according to an even more preferred embodiment, the heating    rate to achieve this temperature is in the range of from from 0.1 to    10° C./min, preferably of from 0.2 to 5° C./min, and-   (v)(b) calcining the thus calcined Cu containing zeolitic material    at a second temperature in the range of from greater than 550 to    750° C., more preferably in the range of from 600 to 650° C.,    wherein, according to an even more preferred embodiment, the heating    rate to achieve this temperature is in the range of from 0.1 to 10°    C./min, preferably of from 0.2 to 5° C./min,    wherein, even more preferably, the heating rate to achieve the    second temperature is lower than the heating rate to achieve the    first temperature, the first heating rate more preferably being in    the range of from 1.75 to 2.25° C./min and the second heating rate    more preferably being in the range of from 0.75 to 1.25° C./min.

The calcination can be effected in any suitable atmosphere, such as, forexample, air, lean air depleted in oxygen, oxygen, nitrogen, watersteam, synthetic air, carbon dioxide. The calcination is preferablyeffected under air. It is also conceivable that calcination is carriedout in a dual mode, i.e. a mode comprising a first calcination in anoxygen-reduced or oxygen-free atmosphere, said mode comprising a secondcalcination in an oxygen-enriched or pure oxygen atmosphere.

The calcination can be carried out in any apparatus suitable for thispurpose. The calcination is preferably effected under static and/ordynamic conditions, such as in a rotating tube, in a belt calciner, in amuffle furnace, in situ in an apparatus in which the zeolitic materialis subsequently used for the intended purpose, for example as amolecular sieve, catalyst, or for any other application described below.A rotating tube and a belt calciner are particularly preferred.

Accordingly, the present invention also relates to above-describedprocess, additionally comprising

-   (iii) separating the Cu containing zeolitic material from the    suspension obtained according to (ii);-   (iv) drying the Cu containing zeolitic material, separated according    to (iii), preferably at a temperature in the range of from 100 to    150° C.;-   (v) calcining the Cu containing zeolitic material, dried according    to (iv), preferably at a temperature in the range of from 300 to    650° C.

According to a conceivable embodiment of the present invention,according to which the zeolitic material obtained according to (ii) isseparated from the suspension obtained from (ii) by means of spraydrying methods or spray granulation methods, the conditions employedduring the separation may be chosen so that during the separation atleast a portion of the zeolitic material is at least partly calcined.Thereby, during the separation, temperatures of preferably at least 300°C. are chosen. This embodiment may provide the advantage that theseparation step, the drying step and at least partly the calcinationstep are combined to a single step.

The present invention also relates to the Cu containing zeoliticmaterial having framework structure CHA, obtainable or obtained byabove-described process.

According to a particularly preferred embodiment, the present inventionis especially characterized in that only in stage (i), a copper sourceis employed. In no subsequent stage of the process any other coppersource is employed. In particular, neither after drying nor aftercalcining, the obtained Cu containing zeolitic material having frameworkstructure CHA is contacted with a copper source. Therefore, the presentinvention allows for a straight-forward direct synthesis of a Cucontaining CHA zeolitic material wherein no post-synthesis stage forcontacting a (copper-free) CHA zeolitic material with a suitable Cusource has to be carried out.

Therefore, the present invention also relates to above-described processand the Cu containing zeolitic material having CHA framework structureobtainable or obtained by this process, wherein, after (i), no Cu sourceis employed. In particular, neither the dried nor the calcined zeoliticmaterial is subjected to any treatments wherein a Cu source is employed.

According to an even more preferred embodiment wherein the Cu containingzeolitic material is synthesized, as described above, in the absence ofsodium, in particular in the absence of alkali metal, the process of thepresent invention allows for an even more simplified process since thetime consuming ion-exchange steps usually to be employed—namely

-   (I) synthesis of the Na form of a CHA zeolitic material,-   (II) calcination, removing the template (SDA) thus forming the H—Na    form,-   (III) transformation to the NH form, and, finally-   (IV) transformation to the Cu²⁺ form    can be avoided.

Consequently, the present invention allows for an economically and alsoecologically advantageous process for the preparation of a Cu containingzeolitic material having CHA framework structure.

In particular, the present invention relates to a Cu containing zeoliticmaterial having CHA framework structure, obtainable or obtained by aprocess, comprising

-   (i) preparation of an aqueous solution containing at least one    source for X₂O₃, preferably at least one source for Al₂O₃, and at    least one source for YO₂, preferably at least one source for SiO₂,    at least one structure directing agent suitable for the preparation    of a zeolitic material having CHA framework structure, preferably a    mixture of 1-adamantyltrimethylammonium hydroxide and    benzyltrimethylammonium hydroxide or a mixture of    1-adamantyltrimethylammonium hydroxide and tetramethylammonium    hydroxide, and at least one Cu source, wherein said aqueous solution    does not contain a phosphorus source;-   (ii) hydrothermal crystallization of the aqueous solution according    to (i) which does not contain a phosphorus source, obtaining a    suspension containing the copper containing zeolitic material having    CHA framework structure;-   (iii) separating the Cu containing zeolitic material from the    suspension obtained according to (ii);-   (iv) drying the Cu containing zeolitic material, separated according    to (iii), preferably at a temperature in the range of from 100 to    150° C., wherein, prior to drying, the separated Cu containing    zeolitic material is washed at least once, preferably with water;-   (v) calcining the Cu containing zeolitic material, dried according    to (iv), preferably at a temperature in the range of from 300 to    650° C.;    wherein, after (i), no Cu source is employed.

According to an even more preferred embodiment, the present inventionrelates to a Cu containing zeolitic material having CHA frameworkstructure, obtainable or obtained by a process, comprising

-   (i) preparation of an aqueous solution containing at least one    source for X₂O₃, preferably at least one source for Al₂O₃, and at    least one source for YO₂, preferably at least one source for SiO₂,    at least one structure directing agent suitable for the preparation    of a zeolitic material having CHA framework structure, preferably a    mixture of 1-adamantyltrimethylammonium hydroxide and    benzyltrimethylammonium hydroxide or a mixture of    1-adamantyltrimethylammonium hydroxide and tetramethylammonium    hydroxide, and at least one Cu source, wherein said aqueous solution    does not contain a phosphorus source;-   (ii) hydrothermal crystallization of the aqueous solution according    to (i) which does not contain a phosphorus source, obtaining a    suspension containing the copper containing zeolitic material having    CHA framework structure;-   (iii) separating the Cu containing zeolitic material from the    suspension obtained according to (ii);-   (iv) drying the Cu containing zeolitic material, separated according    to (iii), preferably at a temperature in the range of from 100 to    150° C., wherein, prior to drying, the separated Cu containing    zeolitic material is washed at least once, preferably with water;-   (v) calcining the Cu containing zeolitic material, dried according    to (iv), preferably at a temperature in the range of from 300 to    650° C.;    wherein, after (i), no Cu source is employed, and wherein, for the    preparation of the aqueous solution according to (i), the at least    one source for YO₂, preferably SiO₂, more preferably exclusively    SiO₂, the at least one source for X₂O₃, preferably Al₂O₃, more    preferably exclusively Al₂O₃, and Cu source, SDA, and water are    employed in such amounts that the aqueous solution obtained    according to (i) exhibits a molar ratio    (nYO₂):X₂O₃    wherein n is at least 10, preferably at least 15, preferably in the    range of from 15 to 70, a molar ratio    (mCu):((nYO₂)+X₂O₃)    wherein m is at least 0.005, preferably in the range of from 0.02 to    0.04, a molar ratio    (qH₂O):((nYO₂)+X₂O₃)    wherein q is at least 20, preferably in the range of from 40 to 50,    and a molar ratio    (pSDA):((nYO₂)+X₂O₃)    wherein p is at least 0.035, preferably in the range of from 0.15 to    0.2.

According to a particularly preferred embodiment, the present inventionrelates to a Cu containing zeolitic material having CHA frameworkstructure, having a composition including of molar ratio(nYO₂):X₂O₃wherein X is a Al, Y is Si, and n is in the range of from 15 to 70, saidzeolitic material having CHA framework structure having a Cu content inthe range of from 2.0 to 4.0 wt.-%, preferably from 2.5 to 3.5 wt.-%,based on the total weight of the calcined zeolitic material, saidzeolitic material being obtained by a process, comprising

-   (i) preparation of an aqueous solution containing at least one    source for Al₂O₃, and at least one source for SiO₂, a mixture of    1-adamantyltrimethyl ammonium hydroxide and benzyltrimethylammonium    hydroxide, or a mixture of 1-adamantyltrimethyl ammonium hydroxide    and tetramethylammonium hydroxide, as structure directing agent    (SDA), and at least one Cu source, wherein said aqueous solution    does not contain a phosphorus source and does not contain a sodium    source, in particular an alkali source, and wherein the pH of the    aqueous solution is in the range of from 12 to 14;-   (ii) hydrothermal crystallization of the aqueous solution according    to (i) which does not contain a phosphor source, obtaining a    suspension containing the Cu containing zeolitic material having CHA    framework structure;-   (iii) separating the Cu containing zeolitic material from the    suspension obtained according to (ii), preferably by filtration;-   (iv) drying the Cu containing zeolitic material, separated according    to (iii), at a temperature in the range of from 100 to 150° C.,    wherein, prior to drying, the separated Cu containing zeolitic    material is washed at least once, preferably with water;-   (v) calcining the Cu containing zeolitic material, dried according    to (iv), at a temperature in the range of from 300 to 600° C.,    preferably stepwise at successive temperatures in the range of from    350 to 550° C., and in the range of from 570 to 600° C.,    respectively;    wherein, after (i), no Cu source is employed, and wherein, for the    preparation of the aqueous solution according to (i), the at least    one source for SiO₂, the at least one source for Al₂O₃, and Cu    source, SDA, and water are employed in such amounts that the aqueous    solution obtained according to (i) exhibits a molar ratio    (nYO₂):X₂O₃    wherein n is in the range of from 15 to 70, a molar ratio    (mCu):((nYO₂)+X₂O₃)    wherein m is in the range of from 0.02 to 0.04, a molar ratio    (qH₂O):((nYO₂)+X₂O₃)    wherein q is in the range of from 40 to 50, and a molar ratio    (pSDA):((nYO₂)+X₂O₃)    wherein p is in the range of from 0.07 to 0.2.    The Cu Containing Zeolitic Material as Such

The present invention also relates to a Cu containing zeolitic materialas such, having framework structure CHA, being free of P, and having acomposition comprising the molar ratio(nYO₂):X₂O₃wherein X is a trivalent element, Y is a tetravalent element and n is atleast 10, preferably at least 15, and wherein the Cu content of thezeolitic material, calculated as elemental Cu, is at least 0.5 wt.-%,based on the total weight of the calcined zeolitic material. In thiscontext, the term “Cu containing zeolitic material as such, havingframework structure CHA, being free of P” relates to the calcinedzeolitic material which is essentially free of water and from which thestructure directing agent and any other organic compounds such asorganic acids have been essentially removed by calcination.

The term “free of P” as used in this context of the present inventionrelates to a P content of the calcined material below 500 ppm,preferably below 300 ppm.

Preferably, n is in the range of from 15 to 70, more preferably in therange of from 15 to 60, more preferably in the range of from 15 to 50.By way of example, especially preferred values of n are 15, 20, 25, 30,40, 45, 50.

The Cu content of the zeolitic material, calculated as elemental Cu, ispreferably at least 1.0 wt.-%, more preferably at least 1.5 wt.-%, morepreferably at least 2.0 wt.-% and even more preferably at least 2.5wt.-%, in each case based on the total weight of the calcined zeoliticmaterial. Even more preferably, the Cu content of the zeolitic material,calculated as elemental Cu, is in the range of up to 5 wt.-%, morepreferably of up to 4.5 wt.-%, more preferably of up to 4.0 wt.-%, andeven more preferably of up to 3.5 wt.-%, in each case based on the totalweight of the calcined zeolitic material. Therefore, preferred ranges ofthe Cu content of the zeolitic material, calculated as elemental Cu, arefrom 1.0 to 5.0 wt.-%, more preferably from 1.5 to 4.5 wt.-%, morepreferably from 2.0 to 4.0 wt.-%, and even more preferably from 2.5 to3.5 wt.-%, in each case based on the total weight of the calcinedzeolitic material.

Therefore, the present invention also relates to the zeolitic materialas described above, wherein the Cu content of the zeolitic material,calculated as elemental Cu, is in the range of from 2.5 to 3.5 wt.-%,based on the total weight of the calcined zeolitic material.

According to a further embodiment of the present invention, the Cucontaining zeolitic material as such, having framework structure CHA,being free of P, additionally contains La, preferably in such an amountthat that the atomic ratio La:Cu is in the range of from 1:10 to 1:100,more preferably in the range of from 1:20 to 1:80, and even morepreferably in the range of from 1:30 to 1:60.

Therefore, the present invention also relates to the zeolitic materialas described above, additionally containing La, preferably in such anamount that the atomic ratio La:Cu is in the range of from 1:10 to1:100.

Generally, all conceivable trivalent elements X and tetravalent elementsY may be contained in the zeolitic framework, are referred to as X₂O₃and YO₂ in the context of the present invention.

Preferably, the trivalent element X is selected from the groupconsisting of Al, B, In, G, and a mixture of two or more thereof.According to an especially preferred embodiment of the presentinvention, the trivalent element X is Al, and even more preferably, Alis the only trivalent element building up the CHA zeolitic frameworkstructure.

Preferably, the tetravalent element Y is selected from group consistingof Si, Sn, Ti, Zr, Ge, and a mixture of two or more thereof. Accordingto an especially preferred embodiment of the present invention, thetetravalent element Y is Si, and even more preferably, no othertetravalent element is used, Si thus being the only tetravalent elementbuilding up the CHA zeolitic framework structure.

Even more preferably, the calcined zeolitic material described above isfree of sodium, in particular free of alkali metal. The term “free ofalkali metal” and “free of sodium”, as used in this context of thepresent invention relates to zeolitic materials having an alkali metalcontent, and a sodium content, respectively, of 1000 ppm or less,preferably 500 ppm or less, more preferably 300 ppm or less.

According to a conceivable embodiment of the present invention, thezeolitic material as described above additionally contains at least onemetal selected from the group consisting of Fe, Co, Ni, Zn, Y, and V.More preferably, the zeolitic material as described above essentiallyconsists of Si, Al, Cu, and O, and optionally La, and containsessentially no further element.

According to one embodiment of the present invention, the edges of atleast 90%, preferably at least 95% of the crystallites of the calcinedzeolitic material as described above or of the calcined zeoliticmaterial obtainable or obtained according to the process as describedabove have a mean length in the range of from 0.05 to 5 micrometer,preferably in the range of from 0.1 to 4 micrometer, more preferably inthe range of from 0.5 to 4 micrometer, more preferably in the range offrom 0.75 to 4 micrometer, and in particular in the range of from 1 to 3micrometer, determined via SEM.

According to a preferred embodiment of the present invention, thecalcined zeolitic material, obtainable or obtained by the process of thepresent invention, or the Cu containing zeolitic material as such,having CHA framework structure, has a TOC content of 0.1 wt.-% or less,based on the total weight of the zeolitic material.

According to a preferred embodiment of the present invention, thecalcined zeolitic material, obtainable or obtained by the process of thepresent invention, or the Cu containing zeolitic material as such,having CHA framework structure, has a BET surface, determined accordingto DIN 66131, in the range of from 300 to 700 m²/g, preferably of from400 to 700 m²/g.

According to a preferred embodiment of the present invention, thecalcined zeolitic material, obtainable or obtained by the process of thepresent invention, or the Cu containing zeolitic material as such,having CHA framework structure, has a Langmuir surface, determinedaccording to DIN 66135, in the range of from 400 to 975 m²/g, preferablyof from 550 to 975 m²/g.

According to a preferred embodiment of the present invention, thecalcined zeolitic material, obtainable or obtained by the process of thepresent invention, or the Cu containing zeolitic material as such,having CHA framework structure, has a thermal stability, determined viadifferential thermal analysis or differential scanning calorimetry, inthe range of from 900 to 1400° C., preferably in the range of from 1100to 1400° C., more preferably in the range of from 1150 to 1400° C.

Moldings

The zeolitic material according to the present invention may be providedin the form of a powder or a sprayed material obtained fromabove-described separation techniques, e.g. decantation, filtration,centrifugation, or spraying.

In many industrial applications, it is often desired on the part of theuser to employ not the zeolitic material as powder or sprayed material,i.e. the zeolitic material obtained by the separation of the materialfrom its mother liquor, optionally including washing and drying, andsubsequent calcination, but a zeolitic material which is furtherprocessed to give moldings. Such moldings are required particularly inmany industrial processes, e.g. in many processes wherein the zeoliticmaterial of the present invention is employed as catalyst or adsorbent.

Accordingly, the present invention also relates to a molding comprisingthe Cu containing zeolitic material having framework structure CHA ofthe present invention.

In general, the powder or sprayed material can be shaped without anyother compounds, e.g. by suitable compacting, to obtain moldings of adesired geometry, e.g. tablets, cylinders, spheres, or the like.

Preferably, the powder or sprayed material is admixed with or coated bya suitable refractory binder. In general, suitable binders are allcompounds which impart adhesion and/or cohesion between the zeoliticmaterial particles to be bonded which goes beyond the physisorptionwhich may be present without a binder. Examples of such binders aremetal oxides, such as, for example, SiO₂, Al₂O₃, TiO₂, ZrO₂ or MgO orclays, or mixtures of two or more of these compounds. Naturallyoccurring clays which can be employed include the montmorillonite andkaolin family, which families include the subbentonites, and the kaolinscommonly known as Dixie, McNamee, Georgia and Florida clays or others inwhich the main mineral constituent is halloysite, kaolinite, dickite,nacrite, or anauxite. Such clays can be used in the raw state asoriginally mined or initially subjected to calcination, acid treatmentor chemical modification. In addition, the zeolitic material accordingto the present invention can be composited with a porous matrix materialsuch as silica-alumina, silica-magnesia, silica-zirconia, silica-thoria,silica-beryllia and silica-titania as well as ternary compositions suchas silica-alumina-thoria, silica-alumina-zirconia,silica-alumina-magnesia and silica-magnesia-zirconia.

Also preferably, the powder or the sprayed material, optionally afteradmixing or coating by a suitable refractory binder as described above,is formed into a slurry, for example with water, which is deposited upona suitable refractory carrier. The slurry may also comprise othercompounds such as, e.g., stabilizers, defoamers, promotors, or the like.Typically, the carrier comprises a member, often referred to as a“honeycomb” carrier, comprising one or more refractory bodies having aplurality of fine, parallel gas flow passages extending therethrough.Such carriers are well known in the art and may be made of any suitablematerial such as cordierite or the like.

The catalysts of the present invention may also be provided in the formof extrudates, pellets, tablets or particles of any other suitableshape, for use as a packed bed of particulate catalyst, or as shapedpieces such as plates, saddles, tubes, or the like.

Also, the catalyst may be disposed on a substrate. The substrate may beany of those materials typically used for preparing catalysts, and willusually comprise a ceramic or metal honeycomb structure. Any suitablesubstrate may be employed, such as a monolithic substrate of the typehaving fine, parallel gas flow passages extending therethrough from aninlet or an outlet face of the substrate, such that passages are open tofluid flow therethrough (referred to as honeycomb flow throughsubstrates). The passages, which are essentially straight paths fromtheir fluid inlet to their fluid outlet, are defined by walls on whichthe catalytic material is disposed as a washcoat so that the gasesflowing through the passages contact the catalytic material. The flowpassages of the monolithic substrate are thin-walled channels, which canbe of any suitable cross-sectional shape and size such as trapezoidal,rectangular, square, sinusoidal, hexagonal, oval, circular, etc. Suchstructures may contain from about 60 to about 400 or more gas inletopenings (i.e., cells) per square inch (2.54 cm×2.54 cm) of crosssection.

The substrate can also be a wall-flow filter substrate, where thechannels are alternately blocked, allowing a gaseous stream entering thechannels from one direction (inlet direction), to flow through thechannel walls and exit from the channels from the other direction(outlet direction). The catalyst composition can be coated on the flowthrough or wall-flow filter. If a wall flow substrate is utilized, theresulting system will be able to remove particulate matter along withgaseous pollutants. The wall-flow filter substrate can be made frommaterials commonly known in the art, such as cordierite, aluminumtitanate or silicon carbide. It will be understood that the loading ofthe catalytic composition on a wall flow substrate will depend onsubstrate properties such as porosity and wall thickness, and typicallywill be lower than loading on a flow through substrate.

The ceramic substrate may be made of any suitable refractory material,e.g., cordierite, cordierite-alumina, silicon nitride, zircon mullite,spodumene, alumina-silica magnesia, zircon silicate, sillimanite, amagnesium silicate, zircon, petalite, alpha-alumina, an aluminosilicate,and the like.

The substrates useful for the catalysts of embodiments of the presentinvention may also be metallic in nature and be composed of one or moremetals or metal alloys. The metallic substrates may be employed invarious shapes such as corrugated sheet or monolithic form. Suitablemetallic supports include the heat resistant metals and metal alloyssuch as titanium and stainless steel as well as other alloys in whichiron is a substantial or major component. Such alloys may contain one ormore of nickel, chromium and/or aluminum, and the total amount of thesemetals may advantageously comprise at least 15 wt. % of the alloy, e.g.,10-25 wt. % of chromium, 3-8 wt. % of aluminum and up to 20 wt. % ofnickel. The alloys may also contain small or trace amounts of one ormore other metals such as manganese, copper, vanadium, titanium, and thelike. The surface or the metal substrates may be oxidized at hightemperatures, e.g., 1000° C. and higher, to improve the resistance tocorrosion of the alloys by forming an oxide layer on the surfaces of thesubstrates. Such high temperature-induced oxidation may enhance theadherence of the refractory metal oxide support and catalyticallypromoting metal components to the substrate.

In alternative embodiments, zeolitic material according to the presentinvention having the CHA structure may be deposited on an open cell foamsubstrate. Such substrates are well known in the art, and are typicallyformed of refractory ceramic or metallic materials.

Use of the Cu Containing Zeolitic Material Having CHA Structure

In general, the zeolitic material described above can be used asmolecular sieve, adsorbent, catalyst, catalyst support or binderthereof. Especially preferred is the use as catalyst. For example, thezeolitic material can be used as molecular sieve to dry gases orliquids, for selective molecular separation, e.g. for the separation ofhydrocarbons or amides; as ion exchanger; as chemical carrier; asadsorbent, in particular as adsorbent for the separation of hydrocarbonsor amides; or as catalyst. Most preferably, the zeolitic materialaccording to the present invention is used as catalyst.

Therefore, the present invention also relates to a catalyst, preferablya molded catalyst, containing the Cu containing zeolitic material havingCHA framework structure as described above.

Moreover, the present invention relates to the use of the Cu containingzeolitic material having CHA framework structure as described above as acatalyst.

Moreover, the present invention relates to a method of catalyzing achemical reaction wherein the Cu containing zeolitic material having CHAframework structure according to the present invention is employed ascatalytically active material.

Among others, said catalyst may be employed as catalyst for theselective reduction (SCR) of nitrogen oxides NO_(x); for the oxidationof NH₃, in particular for the oxidation of NH₃ slip in diesel systems;for the decomposition of N₂O; for soot oxidation; for emission controlin Advanced Emission Systems such as Homogeneous Charge CompressionIgnition (HCCI) engines; as additive in fluid catalytic cracking (FCC)processes; as catalyst in organic conversion reactions; or as catalystin “stationary source” processes.

Therefore, the present invention also relates to a method forselectively reducing nitrogen oxides NO_(x) by contacting a streamcontaining NO_(x) with a catalyst containing the Cu containing zeoliticmaterial having CHA framework structure according to the presentinvention under suitable reducing conditions; to a method of oxidizingNH₃, in particular of oxidizing NH₃ slip in diesel systems, bycontacting a stream containing NH₃ with a catalyst containing the Cucontaining zeolitic material having CHA framework structure according tothe present invention under suitable oxidizing conditions; to a methodof decomposing of N₂O by contacting a stream containing N₂O with acatalyst containing the Cu containing zeolitic material having CHAframework structure according to the present invention under suitabledecomposition conditions; to a method of controlling emissions inAdvanced Emission Systems such as Homogeneous Charge CompressionIgnition (HCCI) engines by contacting an emission stream with a catalystcontaining the Cu containing zeolitic material having CHA frameworkstructure according to the present invention under suitable conditions;to a fluid catalytic cracking FCC process wherein the Cu containingzeolitic material having CHA framework structure according to thepresent invention is employed as additive; to a method of converting anorganic compound by contacting said compound with a catalyst containingthe Cu containing zeolitic material having CHA framework structureaccording to the present invention under suitable conversion conditions;to a “stationary source” process wherein a catalyst is employedcontaining the Cu containing zeolitic material having CHA frameworkstructure according to the present invention.

Most preferably, the zeolitic material according to the presentinvention or the zeolitic material obtainable of obtained according tothe present invention is used as catalyst, preferably as moldedcatalyst, still more preferably as a molded catalyst wherein thezeolitic material is deposited on a suitable refractory carrier, stillmore preferably on a “honeycomb” carrier, for the selective reduction ofnitrogen oxides NO_(x), i.e. for SCR (selective catalytic reduction) ofnitrogen oxides. In particular, the selective reduction of nitrogenoxides wherein the zeolitic material according to the present inventionis employed as catalytically active material is carried out in thepresence ammonia or urea. While ammonia is the reducing agent of choicefor stationary power plants, urea is the reducing agent of choice formobile SCR systems. Typically, the SCR system is integrated in theengine and vehicle design and, also typically, contains the followingmain components: SCR catalyst containing the zeolitic material accordingto the present invention; a urea storage tank; a urea pump; a ureadosing system; a urea injector/nozzle; and a respective control unit.

Therefore, the present invention also relates to a method forselectively reducing nitrogen oxides NO_(x), wherein a gaseous streamcontaining nitrogen oxides NO_(x), preferably also containing ammoniaand/urea, is contacted with the zeolitic material according to thepresent invention or the zeolitic material obtainable of obtainedaccording to the present invention, preferably in the form of a moldedcatalyst, still more preferably as a molded catalyst wherein thezeolitic material is deposited on a suitable refractory carrier, stillmore preferably on a “honeycomb” carrier.

The term nitrogen oxides, NO_(x), as used in the context of the presentinvention designates the oxides of nitrogen, especially dinitrogen oxide(N₂O), nitrogen monoxide (NO), dinitrogen trioxide (N₂O₃), nitrogendioxide (NO₂), dinitrogen tetroxide (N₂O₄), dinitrogen pentoxide (N₂O₅),nitrogen peroxide (NO₃).

The nitrogen oxides which are reduced using a catalyst containing thezeolitic material according to the present invention or the zeoliticmaterial obtainable of obtained according to the present invention maybe obtained by any process, e.g. as a waste gas stream. Among others,waste gas streams as obtained in processes for producing adipic acid,nitric acid, hydroxylamine derivatives, caprolactame, glyoxal,methyl-glyoxal, glyoxylic acid or in processes for burning nitrogeneousmaterials may be mentioned.

Especially preferred is the use of a catalyst containing the zeoliticmaterial according to the present invention or the zeolitic materialobtainable or obtained according to the present invention for removal ofnitrogen oxides NO_(x) from exhaust gases of internal combustionengines, in particular diesel engines, which operate at combustionconditions with air in excess of that required for stoichiometriccombustion, i.e., lean.

Therefore, the present invention also relates to a method for removingnitrogen oxides NO_(x) from exhaust gases of internal combustionengines, in particular diesel engines, which operate at combustionconditions with air in excess of that required for stoichiometriccombustion, i.e., at lean conditions, wherein a catalyst containing thezeolitic material according to the present invention or the zeoliticmaterial obtainable or obtained according to the present invention isemployed as catalytically active material.

When preparing specific catalytic compositions or compositions fordifferent purposes, it is also conceivable to blend the Cu containingmaterial according to the present invention having CHA structure with atleast one other catalytically active material or a material being activewith respect to the intended purpose. It is also possible to blend atleast two different inventive materials which may differ in the Cucontent, and/or in the YO₂:X₂O₃ ratio, preferably in the SiO₂:Al₂O₃ratio, and/or in the presence or absence of a further metal such as atransition metal and/or a lanthanide such as La, and/or in the specificamounts of a further metal such as a transition metal and/or alanthanide such as La, or the like. It is also possible to blend atleast two different inventive materials with at least one othercatalytically active material or a material being active with respect tothe intended purpose. By way of example, it is possible to blend atleast one inventive material with at least one other zeolitic materialhaving CHA structure type and being prepared according to the prior artwherein the zeolitic material, after hydrothermal crystallization, issubjecting to an ion-exchange process wherein, e.g., Cu is introduced.Such mixing of two or more different Cu—CHA materials according toinvention or at least one Cu—CHA material according to the inventionwith at least one other material, such as, e.g., a Cu—CHA materialobtained according to the prior art might be useful as catalyticcompositions allowing for even better meeting low and high temperatureneeds in, e.g., catalytic applications.

The following examples shall further illustrate the process and thematerials of the present invention.

EXAMPLES Determination of Thermal Stability

Throughout the examples, thermal stability of the materials wasdetermined with the thermal analysis instrument STA 449C Jupiter. If thedetermination of thermal stability is referred to in the presentinvention, it shall be understood that said determination refers to thedetermination according to this instrument. The thermal analysisinstrument STA 449C Jupiter is designed to simultaneously measure themass changes (TG) and the calorimetric effects (DSC or DTA) at both highand low temperature. The TG technique measures the temperature-inducedchanges in sample mass. The output signal may be differentiatedelectronically to yield a DTG curve. The DTA technique measures thedifference in temperature between the sample and a reference material.DTA curves provide information on the temperature range wherein aprocess takes place and allow calculation of the value of the enthalpychange (ΔH). Similar information can be obtained from DSC. The followingtest conditions were applied: 10 mg of sample were used for TGA/DTA. Thetemperature ramp rate was 30° C./min from room temperature to 1400° C.

Determination of Crystallinity

Crystallinity, as determined in the examples and throughout theinvention, shall be understood as being determined using a Bruker D 4Endeavor diffractometer, having 4° Söller slits, V20 variable divergenceslits, and scintillator counter as X-ray detector. The followingmeasurement conditions were applied: The samples to be analyzed weremeasured from 2° to 70° (2 theta), or if a quick result is needed from2° to 47° (2 theta) with a shorter time/step. Step width of 0.02° andstep time of 2 seconds were used. The measurements were done withvariable primary and secondary divergence slits. Prior to refinement theraw data were converted to fixed slit data using the data evaluationprogram EVA from Bruker AXS. This had the effect of flattening thebackground and localizing the halo of the amorphous phase. The convertedraw data were then refined in Rietveld program “Topas” by Bruker AXSusing the above mentioned procedure. The background was modeled by aChebychev function of order one which corresponds to a linear functionwhere the slope is a refinable parameter. The fitting range was chosenfrom 8° to 70° (2 theta). The amorphous peak position was fixed at21.95° (2 theta).

Analytical Method:

CHA is a three-dimensional framework zeolite consisting of 4- and6-membered rings of SiO₄ tetrahedra, which form two cages per unit cell.Chabazite crystallizes in a rhombohedral unit cell with space group R-3Mand lattice constants of a=1.352 nm and c=1.468 nm. The diffractogram ofgood crystalline sample shows only sharp diffraction lines and noanisotropic line broadening. Totally amorphous Si/O has a main, broaddiffraction peak in the range between approximately 15° and 35° (2theta) with the peak maximum at around 22° (2 theta). Therefore anyamorphous content in a zeolite sample leads to a decrease of the peakarea under the crystalline peaks in this range and to an increase of theamorphous peak area. The area of the diffraction peaks of the chabazitephase and the amorphous phase was determined with the help of the wholepattern decomposition technique using the Rietveld program “Topas” fromBruker AXS. The degree of crystallinity is defined as the ratio from thearea of the crystalline chabazite phase to the combined area of thecrystalline and amorphous phase (D=Ic/(Ic+Ia)). This method does notrely on additional external standards to be measured or spiking methods,which acquire additional preparation efforts. The diffraction peaks ofthe chabazite were refined by defining the space group and the latticeconstants for the chabazite phase. These determine the position of theindividual (hkl) diffraction lines. The intensities of the (hkl) linesare individually refinable parameters. The amorphous phase was definedby a single peak phase with its position at 22°. The positions as wellas the area of the amorphous peak phase are refinable parameters.Instead of using analytical functions like Pseudo Voigt or Pearson VIIto fit the shape of the (hkl)-lines and the amorphous peak phase, thefundamental parameter approach of “Topas” was used, where theinstrumental parameters of the diffractometer are used to model theshape of the individual peaks. This had the advantage of keeping thenumber of refinable parameters small thereby avoiding cross correlationsbetween refinable parameters.

Example 1 Production of a Cu Containing Zeolitic Material Having CHAFramework Structure

1.1 Preparation of the Synthesis Gel

The following starting materials were employed:

-   -   Deionized water    -   Trimethyl-1-adamantylammonium hydroxide (TMAA, 12.2 wt.-% in        water)    -   Trimethylbenzylammonium hydroxide (TMBA, 40 wt.-% in water        (Aldrich 24,603-4, Lot. S30723-355))    -   Al(OH)₃ (Barcroft 0250)    -   Ammonia (25 wt.-% in water)    -   Cu(NO₃)₂*2.5H₂O    -   Aerosil 200

In a beaker, 1160.60 g of deionized water, 157.2 g of the aqueous TMAAsolution and 91.5 g of the aqueous TMBA solution were admixed andstirred.

In a second beaker, 11.09 g of the copper nitrate were dissolved in105.2 g of the 25 wt.-% aqueous ammonia solution were within about 2 h.Thereby, the solution was stirred.

To the solution of the first beaker, the solution of the second beakerwas added while the solution in the first beaker was stirred. Aftermixing, the obtained solution was stirred for about 20 min.Subsequently, 5.2 of the Al(OH)₃ starting material and 94.0 g of theAerosil were suspended in the solution. The obtained suspension wasstirred for 30 min. The liquid gel having a pH of 13.8 had a compositionwith the following molar ratios: 36 SiO₂:1.2 Al(OH)₃:2.09 TMAA:5.04TMBA:35.6 NH₃:1831H₂O. This gel was transferred in an autoclave.

1.2 Hydrothermal Crystallization

The autoclave was sealed and heated to a temperature of 160° C. within 1h. The temperature of 160° C. was maintained for 60 h. Thereby, themixture in the autoclave was stirred at 200 U/min. The pressure withinthe autoclave was in the range of from 7 to 8 bar.

1.3 Separation, Drying, and Calcination

After the hydrothermal crystallization, the reaction mixture having a pHof 10.5 was cooled to room temperature. The solid material of thesuspension was separated from the mother liquor by filtration and washedwith 3000 ml of deionized water. The washed solid was dried for 10 h at120° C. under air. 107.2 g of dried material was obtained. The driedmaterial was then calcined under air by heating to a temperature of 540°C. at a heating rate of 1° C./min and maintaining this temperature for 5h. Subsequently, the temperature was raised to 595° C. within 60 min,and this temperature was maintained for another 5 h. 87.0 g of calcinedmaterial were obtained.

1.4 Characterization of the Product

Elementary analysis of the calcined material showed 0.02 g of C, 0.02 gof Na, 3.1 g of Cu, 1.4 g of Al and 39.0 g of Si per 100 g of thecalcined material.

The BET surface of the calcined material, determined according to DIN66131, was 527 m²/g, the Langmuir surface area, determined according toDIN 66135, was 705 m²/g. The degree of crystallization was 88%, and themean length of the crystallites was above 100 nm. FIG. 1 shows the XRDpattern of the calcined material having CHA framework type, and FIG. 2shows a typical crystallite of the calcined material, determined by SEM.

Example 2 Production of a Cu Containing Zeolitic Material Having CHAFramework

2.1 Synthesis of the Cu Source

To 21.55 l of a 25 wt.-% solution of NH₃ in H₂O, 2.87 kg of NH₄HCO₃ wereadded. Then 8.81 kg of CuCO₃ were dissolved in this mixture under NH₃atmosphere during 1 h. At the end, 2.5 l of H₂O were added. The solutionwas filtrated after 12 h. An aqueous solution of [Cu(NH₃)₄]CO₃ complex(15.7 wt % Cu) was obtained.

2.2 Preparation of the Synthesis Gel

In a 60 l autoclave, equipped with an anchor mixer and externalcooling/heating means, the following starting materials were admixed:

-   -   The aqueous solution of [Cu(NH₃)₄]CO₃ complex according to 2.1    -   Al(OH)₃ (Barcroft, 78.8 wt.-%)    -   Trimethyl-1-adamantylammonium hydroxide (TMAA, 10.7 wt.-% in        water)    -   Trimethylbenzylammonium hydroxide (TMBA, 10.2 wt.-% in water)    -   Colloidal Ludox AS40 (NH₄ ⁺-stabilized, 40 wt.-% suspension in        H₂O).

The materials were added in the following order:

-   1. H₂O-   2. Al(OH)₃. After the addition of the Al source, the resulting    mixture was stirred for 10 min at room temperature using an anchor    mixer.-   3. TMAA-   4. TMBA. After the addition of the TMBA, the resulting mixture was    stirred for 20 min at room temperature using an anchor mixer.-   5. [Cu(NH₃)₄]CO₃. After the addition of the Cu source, the resulting    mixture was stirred for 10 min at room temperature using an anchor    mixer.-   6. SiO₂ (Ludox). After the addition of the Si source, the resulting    mixture was stirred for 1 h at room temperature using an anchor    mixer.

The materials were added in amounts to obtain a synthesis gel having thefollowing composition:

SiO₂/ Al(OH)₃/ Cu/ NH₃/ H₂O/ TMAA/ TMBA/ mol mol mol mol mol mol mol 361.2 1.0 3.24 1,648 2.08 4.772.3 Hydrothermal Synthesis

After the preparation of the synthesis gel, the autoclave was sealed.Using the external heating means, the synthesis gel in the autoclave washeated to a temperature of 170° C. with a heating rate of 2° C./min. Thereaction mixture in the autoclave was stirred with 150 rpm. After 92 h,crystallization was terminated. During crystallization, 4 samples weretaken to control the degree of crystallinity (see below, section 2.5).

2.4 Separation, Drying, Calcination

After crystallization, the samples and the product obtained after 92 hcrystallization time were filtered and washed with deionized water untilpH 7 (conductivity 90 μS) of the filtrate was reached. Then the productwas dried during 24 h at 120° C. under air. For calcination purposes,the dried samples and the dried product, respectively, were heated underair with a heating rate of 2° C./min to a temperature of 350° C., andsubsequently to a temperature of 600° C. with a heating rate of 1°C./min. The temperature of 600° C. was maintained for 5 h.

2.5 Characterization of the Product

During crystallization, an increase in the degree of crystallinity wasobserved. 80% of crystallinity were reached after about 60 h, and fornext 32 h, only a slight increase of crystallinity to a final value ofabout 85% was observed (see FIG. 3).

The overall yield of 100% crystalline Cu chabazite, based on the amountof silica of the synthesis gel, was 73 mol-%, and 2.7 kg productmaterial were obtained. The solid concentration of the reaction mixturebefore the separation of the solid material from its mother liquor was6.3 wt.-%. The pH of the reaction mixture after hydrothermalcrystallization was 12.

The BET surface of the calcined product, determined according to DIN66131, was 481 m²/g. The molar ratio of Si:Al of the calcined materialwas 28 which corresponds to a molar ratio of SiO₂:Al₂O₃ of 56. The Cucontent of the calcined material, calculated as elemental Cu, was 2.6wt.-%, based on the total weight of the calcined material.

The XRD pattern of the product having CHA framework type (totalcrystallization time 92 h) is shown in FIG. 4.

Example 3 Production of a Cu Containing Zeolitic Material Having CHAFramework Structure

3.1 Preparation of the Synthesis Gel

In a autoclave having a total volume of 60 l and a reaction volume of 40l, equipped with a mixer and external cooling/heating means, 24,587 g ofan aqueous solution of trimethyl-1-adamantylammonium hydroxide (TMAA,4.5 wt.-% in water) and 2,684.8 g of an aqueous solution oftetramethylammonium hydroxide (TMAOH, 25 wt.-% in water) were mixed.Subsequently, the resulting mixture was stirred and 966.2 g of aluminumtriisopropoxide were added. The resulting mixture was stirred for about30 min. Then, 913.2 g of an aqueous solution of [Cu(NH₃)₄]CO₃ complex(15.7 wt % Cu), prepared according to Example 2 (2.1) were added, andthe resulting mixture was stirred for 15 min. Subsequently, 10,892.3 gof Ludox AS40 were added, and the resulting suspension was stirred forabout 30 min.

A sample was taken for determining the pH of the suspension. The pH ofthe suspension was 13.3.

The molar ratios of the synthesis gel were

3.6 TMAOH:2.6 TMAA:2.22 Al isoprop.:1.12 Cu:36 SiO₂:904 H20

3.2 Hydrothermal Synthesis

The autoclave containing the suspension of 3.1 was sealed, and thesuspension was heated to a temperature of 160° C. At 160° C., thepressure in the autoclave was 5.9 bar. Then, the suspension was stirredat 160° C. for 12 h at 120 rpm, and after 12 h, the pressure in theautoclave was 7.2 bar. After another 4 h, i.e. after a totalcrystallization time of 16 h, a first sample (S1) was taken. A secondsample (S2) was taken after a total crystallization time of 38 h.Crystallization was terminated after a total crystallization time of 102h. A sample S3 was taken from the reaction mixture obtained after atotal crystallization time of 102 h.

The remaining reaction mixture was filled in a 60 l plastic drum. Afterhomogenization, 5 l portions of the reaction mixture of the plastic drumwere subjected to different further processes (see sections 3.6 to 3.8).

3.3 Analysis of Sample S1

The pH of sample S1 was 11.8. 260 g of the milky suspension werefiltrated with a porcelain suction filter with a diameter of 25 cm. Thefilter cake was washed with deionized water, and 293.32 g of the wetcake were filled in a porcelain bowl. The wet product was heated to atemperature of 120° C. in air within 30 min and dried at 120° C. for 240min. The dried product was then heated to a temperature of 600° C.within 240 min and calcined in air at 600° C. for 300 min. The yield was31.07 g. A sample of calcined S1 was examined via XRD. It was found thatthe sample was amorphous (see FIG. 5).

3.4 Analysis of Sample S2

The pH of sample S2 was 11.5. 257.45 g of the milky suspension werefiltrated with a porcelain suction filter with a diameter of 25 cm. Thefilter cake was washed with deionized water, and 112.8 g of the wet cakewere filled in a porcelain bowl. The wet product was heated to atemperature of 120° C. in air within 30 min and dried at 120° C. for 240min. The dried product was then heated to a temperature of 600° C.within 240 min and calcined in air at 600° C. for 300 min. The yield was27.29 g. A sample of calcined S2 was examined via XRD (see FIG. 6). TheXRD pattern showed a crystalline zeolitic material having CHA frameworktype.

The degree of crystallinity was 51%, the mean length of the crystallitesof sample S2, determined via SEM/TEM was above 100 nm.

3.5 Analysis of Sample S3

A sample S3 was taken from the reaction mixture obtained after a totalcrystallization time of 102 h. The pH of sample S3 was 11.43. 227.9 g ofthe milky suspension were filtrated with a porcelain suction filter witha diameter if 25 cm. The filter cake was washed with deionized water,and 70 g of the wet cake were filled in a porcelain bowl. The wetproduct was heated to a temperature of 120° C. in air within 30 min anddried at 120° C. for 240 min. The dried product was then heated to atemperature of 600° C. within 240 min and calcined in air at 600° C. for300 min. The yield was 26.07 g. A sample of calcined S3 was examined viaXRD (see FIG. 7). The XRD pattern showed a crystalline zeolitic materialhaving CHA framework type.

The degree of crystallinity was 85%, the mean length of the crystallitesof sample S3, determined via SEM was above 100 nm. Elementary analysisof calcined S3 showed 0.06 g of Na, 2.8 g of Cu, 2.4 g of Al and 39.2 gof Si, in each case per 100 g of calcined S3. The Si:Al ratio ofcalcined S3 was 15.87.

3.6 Spray-Drying of the Reaction Product “as Such” (Sample S4)

2*5 l=10 l of the reaction mixture of the plastic drum, afterhomogenization (see section 3.2 above), were spray-dried. Thespray-drying apparatus is schematically shown in FIG. 8. The nozzle ofthe spray-drier was a two-component nozzle with a diameter of 1.5 mm.The nozzle pressure was 3 bar abs. As drying gas, nitrogen was used witha flow rate of 30 Nm³/h. The temperature of the drying as was 299° C. Asatomizing gas, nitrogen was used with a flow rate of 4 Nm³/h. Thetemperature of the atomizing gas was ambient temperature. Thetemperature of the conus of the spray-drier was in the range of from160-175° C., the temperature of the cyclone in the range of from135-145° C.

In total, 923 g of spray-dried material were obtained, having a moisturelevel of 5.31%.

555.42 g of the spray-dried material were filled in a porcelain bowl.The material was heated to a temperature of 120° C. in air within 30 minand dried at 120° C. for 240 min. The dried product was then heated to atemperature of 600° C. within 240 min and calcined in air at 600° C. for300 min. 425.0 g of calcined material S4 were obtained.

A sample of calcined S4 was examined via XRD (see FIG. 9). The XRDpattern showed a crystalline zeolitic material having CHA frameworktype.

The degree of crystallinity was 88%, the mean length of the crystallitesof sample S4, determined via SEM was above 100 nm (see FIGS. 10-13).

Elementary analysis of calcined S4 showed 0.014 g of C, less than 0.01 gof N, 0.17 g of Na, 2.7 g of Cu, 2.3 g of Al and 39.5 g of Si, in eachcase per 100 g of calcined S4.

The BET surface of calcined S4, determined according to DIN 66131, was492 m²/g, the Langmuir surface, determined according DIN 66135, was 652m²/g.

The thermal behavior of calcined S4 was determined via TGA-IR in Aratmosphere. The following results were obtained (Delta m=massdifference):

sam- ple Delta m Delta m Delta m S4 −3.5% −0.3% −0.9% 40° C.-370° C.370° C.-600° C. 600° C.-1350° C. endoth. peak: 157° C. exoth. peak:1177° C. H₂O3.7 Spray-Drying of the Neutral Reaction Product (Sample S5)

2 kg of the reaction mixture in the plastic drum, after homogenization(see section 3.2 above), were admixed with 2 kg of deionized water. With496 g of 10 wt.-% aqueous HNO₃, the pH of the suspension was adjusted toa value of 7, and the suspension was subjected to filtration. The filtercake was admixed again with deionized water, and the pH of the resultingsuspension was adjusted to a value of 7 with 10 wt.-% aqueous HNO₃.Subsequently, the suspension was filtrated, and the filter cake wastreated once again in the same manner. Then, the solid was washed withdeionized water (15 l) until the conductivity of the filtrate was 120 μS(Microsiemens).

Subsequently, the solid was slurried with deionized water, and theslurry was spray-dried. The spray-drying apparatus is schematicallyshown in FIG. 8. The nozzle of the spray-drier was a two-componentnozzle with a diameter of 1.5 mm. The nozzle pressure was 3 bar abs. Asdrying gas, nitrogen was used with a flow rate of 30 Nm³/h. Thetemperature of the drying as was 299° C. As atomizing gas, nitrogen wasused with a flow rate of 4 Nm³/h. The temperature of the atomizing gaswas ambient temperature. The temperature of the conus of the spray-drierwas in the range of from 165-175° C., the temperature of the cyclone inthe range of from 130-140° C.

In total, 541 g of spray-dried material S5 were obtained, having amoisture level of about 1%.

540 g of the spray-dried material were filled in a porcelain bowl. Thematerial was heated to a temperature of 120° C. in air within 30 min anddried at 120° C. for 240 min. The dried product was then heated to atemperature of 600° C. within 240 min and calcined in air at 600° C. for300 min. 435.5 g of calcined material S5 were obtained.

A sample of calcined S5 was examined via XRD (see FIG. 14). The XRDpattern showed a crystalline zeolitic material having CHA frameworktype.

The degree of crystallinity was 86%, the mean length of the crystallitesof sample S5, determined via SEM was above 100 nm (see FIGS. 15-18).

Elementary analysis of calcined S5 showed 0.018 g of C, less than 0.01 gof N, 0.05 g of Na, 2.7 g of Cu, 2.4 g of Al and 40.0 g of Si, in eachcase per 100 g of calcined S5.

The BET surface of calcined S5, determined according to DIN 66131, was492 m²/g, the Langmuir surface, determined according DIN 66135, was 651m²/g.

The thermal behavior of calcined S5 was determined via TGA-IR in Aratmosphere. The following results were obtained (Delta m=massdifference):

sam- ple Delta m Delta m Delta m S5 −2.6% −0.4% −0.9% 40° C.-335° C.335° C.-600° C. 600° C.-1350° C. endoth. peak: 171° C. exoth. peak:1195° C.3.8 Spray-Drying of the Reaction Product (Sample S6)

2 kg of the reaction mixture in the plastic drum, after homogenization(see section 3.2 above), were subjected to filtration. Subsequently, theobtained solid was slurried with deionized water, and the slurry wasspray-dried. The spray-drying apparatus is schematically shown in FIG.8. The nozzle of the spray-drier was a two-component nozzle with adiameter of 1.5 mm. The nozzle pressure was 3 bar abs. As drying gas,nitrogen was used with a flow rate of 30 Nm³/h. The temperature of thedrying as was 299° C. As atomizing gas, nitrogen was used with a flowrate of 4 Nm³/h. The temperature of the atomizing gas was ambienttemperature. The temperature of the conus of the spray-drier was in therange of from 165-175° C., the temperature of the cyclone in the rangeof from 135-150° C.

In total, 541 g of spray-dried material S6 were obtained, having amoisture level of about 1.52%.

480 g of the spray-dried material S6 were filled in a porcelain bowl.The material was heated to a temperature of 120° C. in air within 30 minand dried at 120° C. for 240 min. The dried product was then heated to atemperature of 600° C. within 240 min and calcined in air at 600° C. for300 min. 377.5 g of calcined material S6 were obtained.

Elementary analysis of calcined S6 showed 0.021 g of C, less than 0.01 gof N, 0.09 g of Na, 2.6 g of Cu, 2.4 g of Al and 41.0 g of Si, in eachcase per 100 g of calcined S6.

Example 4 SCR Test of Sample S5 According Example 3

4.1 Preparation of a Slurry

90 g of the spray-dried and calcined zeolitic material containing Cu andhaving CHA framework structure, obtained according to example 3 (sample5) were mixed with 215 ml of deionized water. The mixture wasball-milled for 11 hours to obtain a slurry which comprised 90%particles smaller than 10 micrometer. 15.8 g of zirconium acetate indilute acetic acid were added to the slurry with agitation. In thefinally calcined honeycomb, ZrO₂ is then formed, acting as bindermaterial for the adhesion of particles to the honeycomb.

4.2 Coating

The slurry was coated onto 1″D×3″L cellular ceramic cores having a celldensity of 400 cpsi (cells per square inch=cells per (2.54 cm)²) and awall thickness of 6.5 mm. The coated cores were dried at 110° C. for 3hours and calcined at 400° C. for 1 hour. The coating process wasrepeated once to obtain a target washcoat loading of 2.4 g/in³ (2.4g/(2.54 cm)³). The washcoat loading is defined as the dry weight gain onthe honeycomb with respect to the volume.

4.3 Measuring NOx Selective Catalytic Reduction (SCR) Efficiency

Nitrogen oxides selective catalytic reduction (SCR) efficiency andselectivity of a fresh catalyst core were measured by adding a feed gasmixture of 500 ppm of NO, 500 ppm of NH₃, 10% O₂, 5% H₂O, balanced withN₂ to a steady state reactor containing a 1″D×3″L catalyst core.

For the catalytic test, the washcoated core was shaped into a squarecross section wrapped with a ceramic insulation mat and placed inside anInconel reactor tube heated by an electrical furnace. The gases, O₂(from air), N₂ and H₂O were preheated in a preheater furnace beforeentering the reactor. The reactive gases NO and NH₃ were introducedbetween the preheater furnace and the reactor.

The reaction was carried at a space velocity of 80,000 h⁻¹ across a 150°C. to 460° C. temperature range. Space velocity is defined as the gasflow rate comprising the entire reaction mixture divided by thegeometric volume of the catalyst core. These conditions define thestandard test for fresh catalysts.

FIG. 19 shows the results of the SCR test, indicating the catalyticefficiency and selectivity of the fresh catalyst. Generally, there is adesire to provide materials which exhibit high performance over a widetemperature range, particularly with improvement of low temperatureperformance. Performance includes NOx conversion but, also selectivityof the SCR to N₂ reflected by minimizing the formation of N₂O. It can beseen that this catalyst according to the invention exhibits high NOxconversion across the entire temperature window together with low N₂Omake (<10 ppm N₂O).

4.4 Measuring Hydrothermal Stability of the Catalyst

Hydrothermal stability of the catalyst was measured by hydrothermalaging of the fresh catalyst core described above under section 4.2 inthe presence of 10 wt.-% H₂O at 850° C. for 6 hours, followed bymeasurement of the nitrogen oxides SCR efficiency and selectivity by thesame process, as outlined above under section 4.3, for the SCRevaluation on a fresh catalyst core.

The results of the SCR efficiency and selectivity of the aged catalystis depicted in FIG. 20. Generally, there is a desire to improvehydrothermal stability over existing zeolitic materials, for example,catalyst materials which are stable at temperatures up to at least about650° C. and higher, for example in the range of about 700° C. to about800° C. It can be seen that this catalyst according to the inventionmaintains high NOx conversion over the entire temperature window whilstmaintaining high selectivity towards nitrogen which is reflected in thelow N₂O make (<20 ppm N₂O).

Example 5 Production of a Cu Containing Zeolitic Material Having CHAFramework Structure, Additionally Containing La

5.1 Preparation of the Synthesis Gel

The following starting materials were employed:

-   -   Deionized water    -   Trimethyl-1-adamantylammonium hydroxide (TMAA, 13.4 wt.-% in        water, Sachen Lot. A7089OX16007)    -   Tetramethylammonium hydroxide (TMAOH, 25 wt.-% in water (Aldrich        331633, Lot. A337872))    -   Aluminum triisopropylate (Aldrich 22,041-8, Lot. S42369-457)    -   [Cu(NH₃)₄]CO₃ complex (15.7 wt % Cu), prepared according to        Example 2 (2.1)    -   La(NO₃)₃×6 H₂O    -   Ludox AS40

In a beaker, 612.15 g of deionized water and 309.29 g of the aqueousTMAA solution were admixed. Subsequently, 99 g of the aqueous TMAOHsolution were admixed and stirred for 10 min at room temperature.Subsequently, 0.92 g La(NO₃)₃×6 H₂O were added while the mixture wasstirred. Then, 34.7 g of Aluminum triisopropylate were added, and theresulting suspension was stirred for about 60 min. Subsequently, 36.2 gof the [Cu(NH₃)₄]CO₃ solution were added and stirred for about 10 min.Subsequently, 408.3 g Ludox AS40 were added, and the resultingsuspension was stirred for about 20 min.

The pH of the obtained suspension was 13.3.

The suspension had a composition with the following molar ratios: 36SiO₂:2.25 Al isprop.:2.6 TMAA:3.6 TMAOH:1.12 Cu amine:455H₂O:0.028La(NO₃)₃×6 H₂O. This gel was transferred in an autoclave.

5.2 Hydrothermal Crystallization

The autoclave was sealed and heated to a temperature of 160° C. Thetemperature of 160° C. was maintained for 12 h. Thereby, the mixture inthe autoclave was stirred at 200 rpm (revolutions/minute). The pressurewithin the autoclave was 7 bar at the beginning, and 7.2 bar after 12 h.Then, heating of the autoclave was stopped, the autoclave was cooled to50° C., and the reaction mixture was stirred for 30 min. Subsequently,the autoclave was heated to 160° C., and stirred for 90 h while thetemperature was maintained at 160° C.

5.3 Separation, Drying, and Calcination

After the hydrothermal crystallization, the resulting suspension had apH of 11.57. This suspension was admixed (1:1) with deionized water, andthe pH of the resulting suspension was adjusted to 7.47 with 650 g of 5%HNO₃. Then, the suspension was filtrated with a porcelain suction filterwith a diameter of 15 cm. The filter cake was washed with deionizedwater, and 380 g of the wet cake were filled in a porcelain bowl. Thewet product was heated to a temperature of 120° C. in air within 30 minand dried at 120° C. for 240 min. The dried product was then heated to atemperature of 600° C. within 240 min and calcined in air at 600° C. for300 min. The yield was 179.99 g. A sample of the calcined material wasexamined via XRD, and it was found that a zeolite having CHA frameworkhad been obtained (see FIG. 21).

5.4 Characterization of the Product

Elementary analysis of calcined material obtained according to 5.3showed 0.015 g of C, less than 0.5 g of N, 0.06 g of Na, 2.6 g of Cu,2.2 g of Al and 38.0 g of Si, in each case per 100 g of calcinedmaterial.

The BET surface of the calcined material, determined according to DIN66131, was 488 m²/g, the Langmuir surface area, determined according toDIN 66135, was 675.5 m²/g. The degree of crystallization was 92%, andthe mean length of the crystallites was above 100 nm. Typicalcrystallites had a mean length of about 3-4 micrometers (see FIGS.22-24).

The thermal behavior of calcined material was determined via TG/DTA/IR.The following results were obtained (Delta m=mass difference):

sample Delta m Delta m calcined −3.8% −0.8% material of (30° C.-713° C.)(713° C.-1350° C.) Example 5 endoth. peak 187.2° C. exoth. peaks 1182.7°C. and (FTIR analysis) H₂O, traces of CO₂ 1302.1° C. CO₂, traces of H₂Ound CO

It was found that the material had a decomposition temperature of about1182.7° C. and a recrystallization temperature of about 1302.1° C. Itcan be noted that the presence of La has resulted in an increase in thedecomposition temperature when compared to Example 3.6

Example 6 Production of a Cu Containing Zeolitic Material Having CHAFramework Structure

6.1 Preparation of the Synthesis Gel

The following starting materials were employed:

-   -   Trimethyl-1-adamantylammonium hydroxide (TMAA, 13.4 wt.-% in        water, Sachen Lot. A7089OX16007)    -   Tetramethylammonium hydroxide (TMAOH, 25 wt.-% in water (Aldrich        331633, Lot. A337872))    -   Aluminum triisopropylate (Aldrich 22,041-8, Lot. S42369-457)    -   [Cu(NH₃)₄]CO₃ complex (15.7 wt % Cu), prepared according to        Example 2 (2.1)    -   Ludox AS40

In a beaker, 222.8 g of TMAA and 696.7 g of TMAOH solution were mixed.This solution was stirred for 10 min at room temperature. Then, 94.1 gof Aluminum triisopropylate were added, and the resulting suspension wasstirred for about 60 min. Subsequently, 67.4 g of the [Cu(NH₃)₄]CO₃solution were added and stirred for about 10 min. Subsequently, 918.9 gLudox AS40 were added, and the resulting suspension was stirred forabout 20 min.

The pH of the obtained suspension was 13.6.

The suspension had a composition with the following molar ratios: 36SiO₂:2.7 Al isprop.:2.6 TMAA:3.6 TMAOH:0.096 Cu amine:450 H₂O. This gelwas transferred in an autoclave.

6.2 Hydrothermal Crystallization

The autoclave was sealed and heated to a temperature of 170° C. Thetemperature of 170° C. was maintained for 120 h. Thereby, the mixture inthe autoclave was stirred at 200 rpm (revolutions/minute).

6.3 Separation, Drying, and Calcination

After the hydrothermal crystallization, the resulting suspension had apH of 11.26. This suspension was admixed (1:1) with deionized water, andthe pH of the resulting suspension was adjusted to 7.47 with about 650 gof 5% HNO₃. Then, the suspension was filtrated with a porcelain suctionfilter with a diameter of 15 cm. The wet product was heated to atemperature of 120° C. in air within 30 min and dried at 120° C. for 240min. The dried product was then heated to a temperature of 600° C.within 240 min and calcined in air at 600° C. for 300 min. The yield was403.5 g. A sample of the calcined material was examined via XRD, and itwas found that a zeolite having CHA framework had been obtained (seeFIG. 25).

6.4 Characterization of the Product

Elementary analysis of calcined material obtained according to 5.3showed 0.026 g of C, less than 0.5 g of N, 0.038 g of Na, 2.2 g of Cu,2.9 g of Al and 39.0 g of Si, in each case per 100 g of calcinedmaterial.

The BET surface of the calcined material, determined according to DIN66131, was 459.7 m²/g, the Langmuir surface area, determined accordingto DIN 66135, was 638.5 m²/g. The degree of crystallization was 92%, andthe mean length of the crystallites was above 100 nm. Typicalcrystallites had a mean length of about 2-5 micrometers (see FIGS.26-28).

The thermal behavior of calcined material was determined via TG/DTA/IR.The following results were obtained (Delta m=mass difference):

sample Delta m Delta m calcined −5.3% −1.2% material of (30° C.-578° C.)(578° C.-1375° C.) Example 6 H₂O, traces of CO₂ exoth. peaks 1188.5° C.(FTIR analysis) and 1329.3° C. CO₂, traces of H₂O, NH3 and CO

It was found that the material had a decomposition temperature of about1188.5° C. and a recrystallization temperature of about 1329.3° C.

Example 7 SCR Test of Sample According Example 6

7.1 Preparation of a Slurry

150 g of the spray-dried and calcined zeolitic material containing Cuand having CHA framework structure, obtained according to example 6 wasmixed with 358 ml of deionized water. The mixture was ball-milled for 11hours to obtain a slurry which comprised 90% particles smaller than 10micrometer. 26 g of zirconium acetate in dilute acetic acid (containing30% ZrO2) were added to the slurry with agitation.

7.2 Coating

The slurry was coated onto 1″D×3″L cellular ceramic cores having a celldensity of 65 cpsc (cells per square cm) (400 cpsi (cells per squareinch)) and a wall thickness of 6.5 mm. The coated cores were dried at110° C. for 3 hours and calcined at 400° C. for 1 hour. The coatingprocess was repeated once to obtain a target washcoat loading of 0.146g/cm³ (2.4 g/in³). The washcoat loading is defined as the dry weightgain on the honeycomb with respect to volume.

7.3 Measuring NOx Selective Catalytic Reduction (SCR) Efficiency

Nitrogen oxides selective catalytic reduction (SCR) efficiency andselectivity of a fresh catalyst core were measured by adding a feed gasmixture of 500 ppm of NO, 500 ppm of NH₃, 10% O₂, 5% H₂O, balanced withN₂ to a steady state reactor containing a 1″D×3″L catalyst core.

For the catalytic test, the washcoated core was shaped into a squarecross section wrapped with a ceramic insulation mat and placed inside anInconel reactor tube heated by an electrical furnace. The gases, O₂(from air), N₂ and H₂O were preheated in a preheater furnace beforeentering the reactor. The reactive gases NO and NH₃ were introducedbetween the preheater furnace and the reactor.

The reaction was carried at a space velocity of 80,000 h⁻¹ across a 150°C. to 460° C. temperature range. Space velocity is defined as the gasflow rate comprising the entire reaction mixture divided by thegeometric volume of the catalyst core. These conditions define thestandard test for fresh catalysts.

FIG. 29 shows the results of the SCR test, indicating the catalyticefficiency and selectivity of the fresh catalyst. Generally, there is adesire to provide materials which exhibit high performance over a widetemperature range, particularly with improvement of low temperatureperformance. Performance includes NOx conversion but, also selectivityof the SCR to N₂ reflected by minimizing the formation of N₂O. It can beseen that this catalysts exhibits high NOx conversion across the entiretemperature window together with low N₂O make (<10 ppm N₂O).

7.4 Measuring Hydrothermal Stability of the Catalyst

Hydrothermal stability of the catalyst was measured by hydrothermalaging of the fresh catalyst core described above under section 4.2 inthe presence of 10 wt.-% H₂O at 850° C. for 6 hours, followed bymeasurement of the nitrogen oxides SCR efficiency and selectivity by thesame process, as outlined above under section 4.3, for the SCRevaluation on a fresh catalyst core.

The results of the SCR efficiency and selectivity of the aged catalystis depicted in FIG. 30. Generally, there is a desire to improvehydrothermal durability over existing zeolitic materials, for example,catalyst materials which are stable at temperatures up to at least about650° C. and higher, for example in the range of about 700° C. to about900° C. It can be seen that this catalyst maintains high NOx conversionover the entire temperature window whilst maintaining high selectivitytowards nitrogen which is reflected in the low N₂O make (<20 ppm N₂O).

CE 1 (Example According to Prior Art) Production of a Cu ContainingZeolitic Material Having CHA Framework Structure Via Ion Exchange

CE 1.1 Preparation of a Powder Zeolitic Material Having CHA FrameworkStructure

The following starting materials were employed:

-   -   Deionized water    -   Trimethyl-1-adamantylammonium hydroxide (TMAA, 13.4 wt.-% in        water, Sachen Lot. A7089OX16007)    -   Aluminum triisopropoxide (Aldrich 22,041-8, Lot. S42369-457)    -   Ludox AS40    -   Sodium hydroxide (50% solution)

38.95 kg of adamantyl solution were added to the autoclave.Subsequently, 2.65 kg sodium hydroxide solution were added withagitation. Mixing was carried out until the solution was clear (about 30minutes). Then, 4.26 kg aluminum triisopropoxide (ATIP) were addedwithin 5-15 minutes. Mixing was continued until the solids were reactedand the solution was a uniform suspension (about 2 hours). Then, 50 kgLudox AS-40 were added with stirring.

The suspension had a composition with the following molar ratios: 36SiO₂:1.1 Al₂O₃:2.6 TMAA:1.8 Na₂O:377H₂O.

CE 1.2 Hydrothermal Crystallization

The autoclave was sealed and heated to a temperature of 170° C. Thetemperature of 170° C. was maintained for 20 hours. Thereby, the mixturein the autoclave was stirred at 200 rpm (revolutions/minute). Thepressure within the autoclave was 7.8 bar. The pH was 13.4 at thebeginning of the reaction. After 20 hours, heating of the autoclave wasstopped and the autoclave was cooled to 35° C.

CE 1.3 Separation, Drying, and Calcination

After the hydrothermal crystallization, the resulting suspension had apH of 11.9. Per 1000 kg of reactor content 168 kg of diluted acid wereadded. About 80% of the calculated total amount of premixed nitric acid(10 wt.-% aqueous solution) was fed into the reactor under agitation.About 20% were slowly added in smaller portions until pH reached about7-7.5. The entire composition was fed to the filtration device.

The suspension was filtrated with a filter press. The filter cake waswashed with deionized water to a conductivity of 200 microSiemens/cm.The wet product was heated to a temperature of 120° C. in air within 30min and dried at 120° C. for 240 min. The dried product was then heatedto a temperature of 600° C. within 240 min and calcined in air at 600°C. for 300 min. A sample of the calcined material was examined via XRD,and it was found that a zeolite having CHA framework had been obtained.

CE 1.4 Ammonium Exchange

The ammonium form was produced via ion-exchange of CE 1.3. An ammoniumnitrate solution was prepared by mixing 55.6 g of 54 wt.-% ammoniumnitrate with 530 g of deionized water at 80° C. 300 g of the zeoliticmaterial of CE 1.3 was then added to this solution. The ion-exchangereaction between the Na/H-form of the zeolitic material and the ammoniumions was carried out by agitating the slurry at 60° C. for 1 hour. ThepH was between 2.7 and 2.4 during the reaction. The resulting mixturewas then filtered, washed until the filtrate had a conductivity of <200microSiemens/cm before the washed sample was air dried.

CE 1.5 Copper Exchange

A copper (II) acetate monohydrate solution was prepared by dissolving89.8 g of copper acetate salt in 1.125 l of deionized water at 70° C.300 g of the zeolitic material of CE 1.4 was then added to thissolution. An ion-exchange reaction between the NH₄ ⁺-form of thezeolitic material and the copper ions was carried out by agitating theslurry at 70° C. for 1.5 hours. The pH was between 4.8 and 4.5 duringthe reaction. The resulting mixture was then filtered, washed until thefiltrate had a conductivity of <200 microSiemens/cm, which indicatedthat substantially no soluble or free copper remained in the sample, andthe washed sample was dried at 90° C. The obtained Cu containingmaterial comprised Cu at 2.4% by weight and Na at 104 ppm. TheSiO₂:Al₂O₃ was 30:1.

CE 1.6 SCR Test of the Material of CE 1.5

CE 1.6.1 Preparation of a Slurry

197 g of the zeolitic material containing Cu and having CHA frameworkstructure, obtained according to CE 1.5 was mixed with 280.4 ml ofdeionized water. The mixture was ball-milled for 20 minutes to obtain aslurry which comprised 90% particles smaller than 10 micrometer. 27.38 gof zirconium acetate in dilute acetic acid (containing 30% ZrO₂) wereadded to the slurry with agitation.

CE 1.6.2 Coating

The slurry was coated onto 1″D×3″L cellular ceramic cores having a celldensity of 65 cpsc (cells per square cm) (400 cpsi (cells per squareinch)) and a wall thickness of 6.5 mm. The coated cores were dried at110° C. for 3 hours and calcined at 400° C. for 1 hour. The coatingprocess was repeated once to obtain a target washcoat loading of 0.146g/cm³ (2.4 g/in³). The washcoat loading is defined as the dry weightgain on the honeycomb with respect to volume.

CE 1.6.3 Measuring NOx Selective Catalytic Reduction (SCR) Efficiency

Nitrogen oxides selective catalytic reduction (SCR) efficiency andselectivity of a fresh catalyst core were measured by adding a feed gasmixture of 500 ppm of NO, 500 ppm of NH₃, 10% O₂, 5% H₂O, balanced withN₂ to a steady state reactor containing a 1″D×3″L catalyst core.

For the catalytic test, the washcoated core was shaped into a squarecross section wrapped with a ceramic insulation mat and placed inside anInconel reactor tube heated by an electrical furnace. The gases, O₂(from air), N₂ and H₂O were preheated in a preheater furnace beforeentering the reactor. The reactive gases NO and NH₃ were introducedbetween the preheater furnace and the reactor.

The reaction was carried at a space velocity of 80,000 h⁻¹ across a 150°C. to 460° C. temperature range. Space velocity is defined as the gasflow rate comprising the entire reaction mixture divided by thegeometric volume of the catalyst core. These conditions define thestandard test for fresh catalysts.

The results of the SCR efficiency and selectivity of the fresh catalystis depicted in FIG. 31.

CE 1.6.4 Measuring Hydrothermal Stability of the Catalyst

Hydrothermal stability of the catalyst was measured by hydrothermalaging of the fresh catalyst core described above under section 4.2 inthe presence of 10 wt.-% H₂O at 850° C. for 6 hours, followed bymeasurement of the nitrogen oxides SCR efficiency and selectivity by thesame process, as outlined above under section 4.3, for the SCRevaluation on a fresh catalyst core.

The results of the SCR efficiency and selectivity of the aged catalystis depicted in FIG. 32.

Example 8 Production of a Cu Containing Zeolitic Material Having CHAFramework Structure

8.1 Preparation of the Synthesis Gel

The following starting materials were employed:

-   -   Trimethyl-1-adamantylammonium hydroxide (TMAA, 13.4 wt.-% in        water, Sachen Lot. A7089OX16007)    -   Tetramethylammonium hydroxide (TMAOH, 25 wt.-% in water (Aldrich        331633, Lot. A337872))    -   Aluminum triisopropylate (Aldrich 22,041-8, Lot. S42369-457)    -   [Cu(NH₃)₄]CO₃ complex (14.5 wt % Cu), prepared according to        Example 2 (2.1)    -   Ludox AS-40    -   seeds of a one-pot CuCHA

In a 1600 liter autoclave, 190.9 kg of TMAA and 59.7 kg of TMAOHsolution were mixed. This solution was stirred for 10 min at roomtemperature. Then, 25.2 kg of aluminum triisopropylate were added, andthe resulting suspension was stirred for about 60 min. Subsequently,19.1 kg of the [Cu(NH₃)₄]CO₃ solution were added and stirred for about10 min. Subsequently, 246.2 kg Ludox AS-40 were added, and the resultingsuspension was stirred for about 20 min.

The pH of the obtained suspension was 13.5.

The suspension had a composition with the following molar ratios: 36SiO₂:2.7 Al isprop.:2.6 TMAA:3.6 TMAOH:0.96 Cu amine:450 H₂O. Then, 5 kgof 79% crystalline CuChabazite were added as seeds in the spray driedform.

8.2 Hydrothermal Crystallization

The autoclave was sealed and heated to a temperature of 170° C. Thetemperature of 170° C. was maintained for 96 h. Thereby, the mixture inthe 1600 liter autoclave was stirred at 49 rpm (revolutions/minute).In-situ samples were taken after 48, 72 and 96 hours.

8.3 Separation, Drying, and Calcination

After the hydrothermal crystallization, the resulting suspension had apH of 11.4. This suspension was admixed (1:1) with deionized water, andthe pH of the resulting suspension was adjusted to 7.5 with 5% HNO₃.Then, the suspension was filtrated with a 400 liter porcelain suctionfilter with a diameter of 80 cm. The wet product was then spray dried(cylcon temperature was 130° C. and drying gases temperature was 300°C.). The dried product was then calcined in a rotary kiln at atemperature of 600° C. to remove the template and ensure a C contentless than 0.1 wt %. A sample of the calcined material was examined viaXRD, and it was found that a zeolite having CHA framework had beenobtained (see FIG. 33).

8.4 Characterization of the Product

Elementary analysis of the calcined material obtained according to 8.3showed less than 0.1 g of C, less than 0.5 g of N, 0.05 g of Na, 1.8 gof Cu, 2.4 g of Al and 32.0 g of Si, in each case per 100 g of calcinedmaterial. This correlates to a SiO₂:Al₂O₃ ratio of 25.6.

The BET surface of the calcined material, determined according to DIN66131, and the Langmuir surface area, determined according to DIN 66135,are listed in the table hereinunder with details of the crystallization.Typical crystallites had a mean length of about 1.5-3 micrometers (seeFIGS. 34-36).

Crystallization Gel Langmuir Surface BET Surface/ Time/h OH/Si XRD/%Area/(m²/g) (m²/g) 48 0.172 79 680.5 502.3 72 0.172 82 660.8 492.0 960.172 80 663.6 494.1

The characterization of the products with crystallization time indicatethat the crystallization is complete after at most 48 hours. It isconceived that shorter crystallization times may be possible.

Example 9 SCR Test of Sample According Example 8

9.1 Preparation of a Slurry

150 g of the spray-dried and calcined zeolitic material containing Cuand having CHA framework structure, obtained according to example 8 wasmixed with 358 ml of deionized water. The mixture was ball-milled for 11hours to obtain a slurry which comprised 90% particles smaller than 10micrometer. 26 g of zirconium acetate in dilute acetic acid (containing30% ZrO₂) were added to the slurry with agitation

9.2 Coating

The slurry was coated onto 1″D×3″L cellular ceramic cores having a celldensity of 65 cpsc (cells per square cm) (400 cpsi (cells per squareinch)) and a wall thickness of 6.5 mm. The coated cores were dried at110° C. for 3 hours and calcined at 400° C. for 1 hour. The coatingprocess was repeated once to obtain a target washcoat loading of 0.146g/cm³ (2.4 g/in³). The washcoat loading is defined as the dry weightgain on the honeycomb with respect to volume.

9.3 Measuring NOx Selective Catalytic Reduction (SCR) Efficiency

Nitrogen oxides selective catalytic reduction (SCR) efficiency andselectivity of a fresh catalyst core were measured by adding a feed gasmixture of 500 ppm of NO, 500 ppm of NH₃, 10% O₂, 5% H₂O, balanced withN₂ to a steady state reactor containing a 1″D×3″L catalyst core.

For the catalytic test, the washcoated core was shaped into a squarecross section wrapped with a ceramic insulation mat and placed inside anInconel reactor tube heated by an electrical furnace. The gases, O₂(from air), N₂ and H₂O were preheated in a preheater furnace beforeentering the reactor. The reactive gases NO and NH₃ were introducedbetween the preheater furnace and the reactor.

The reaction was carried at a space velocity of 80,000 h⁻¹ across a 150°to 460° C. temperature range. Space velocity is defined as the gas flowrate comprising the entire reaction mixture divided by the geometricvolume of the catalyst core. These conditions define the standard testfor fresh catalysts.

FIG. 37 shows the results of the SCR test, indicating the catalyticefficiency and selectivity of the fresh catalyst. Generally, there is adesire to provide materials that exhibit high performance over a widetemperature range, particularly with improvement of low temperatureperformance. Performance includes NOx conversion but also selectivity ofthe SCR to N₂ reflected by minimizing the formation of N₂O. It can beseen that this catalysts exhibits high NOx conversion across the entiretemperature window together with low N₂O make (<10 ppm N₂O). Theseperformance characteristics are a large improvement over currentcommercial catalysts such as FeBeta using the same testing conditions.

9.4 Measuring Hydrothermal Stability of the Catalyst

Hydrothermal stability of the catalyst was measured by hydrothermalaging of the fresh catalyst core described above under section 9.2 inthe presence of 10 wt.-% H₂O at 850° C. for 6 hours, followed bymeasurement of the nitrogen oxides SCR efficiency and selectivity by thesame process, as outlined above under section 9.3, for the SCRevaluation on a fresh catalyst core.

The results of the SCR efficiency and selectivity of the aged catalystis depicted in FIG. 38. There is a desire to improve hydrothermaldurability over existing zeolitic materials, for example, catalystmaterials which are stable at temperatures up to at least about 650° C.and higher, for example in the range of about 700° C. to about 900° C.It can be seen that this catalyst maintains high NOx conversion over theentire temperature window whilst maintaining high selectivity towardsnitrogen which is reflected in the low N₂O make (<20 ppm N₂O).

Example 10 Production of a Cu Containing Zeolitic Material Having CHAFramework Structure

10.1 Preparation of the Synthesis Gel

The following starting materials were employed:

-   -   Trimethyl-1-adamantylammonium hydroxide (TMAA, 13.4 wt.-% in        water, Sachen Lot. A7089OX16007)    -   Tetramethylammonium hydroxide (TMAOH, 25 wt.-% in water (Aldrich        331633, Lot. A337872))    -   Aluminum triisopropylate (Aldrich 22,041-8, Lot. S42369-457)    -   [Cu(NH₃)₄]CO₃ complex (14.5 wt % Cu), prepared according to        Example 2 (2.1)    -   Ludox AS40    -   seeds of a one-pot CuCHA

In a beaker, 718.6 g of TMAA and 188.8 g of TMAOH solution were mixed.This solution was stirred for 10 min at room temperature. Then, 94.8 gof aluminum triisopropylate were added, and the resulting suspension wasstirred for about 60 min. Subsequently, 71.7 g of the [Cu(NH₃)₄]CO₃solution were added and stirred for about 10 min. Subsequently, 926.1 gLudox AS40 were added, and the resulting suspension was stirred forabout 20 min.

The pH of the obtained suspension was 14.1.

The suspension had a composition with the following molar ratios: 36SiO₂:2.7 Al isprop.:2.6 TMAA:3.0 TMAOH:0.96 Cu amine:448H₂O. This gelwas transferred in a 2.5 L autoclave. Then 20 g of 79% crystallineCuChabazite were added as seeds in the spray dried form.

10.2 Hydrothermal Crystallization

The autoclave was sealed and heated to a temperature of 160° C. Thetemperature of 160° C. was maintained for 48 h. Thereby, the mixture inthe autoclave was stirred at 200 rpm (revolutions/minute).

10.3 Separation, Drying, and Calcination

After the hydrothermal crystallization, the resulting suspension had apH of 11.6. This suspension was admixed (1:1) with deionized water, andthe pH of the resulting suspension was adjusted to 7.5 with 5% HNO₃.Then, the suspension was filtrated with a porcelain suction filter witha diameter of 15 cm. The wet product was heated to a temperature of 120°C. in air within 30 min and dried at 120° C. for 240 min. The driedproduct was then heated to a temperature of 600° C. within 240 min andcalcined in air at 600° C. for 300 min. The yield was 406 g. A sample ofthe calcined material was examined via XRD, and it was found that azeolite having CHA framework had been obtained (see FIG. 39).Crystallinity was reported as 90%.

10.4 Characterization of the Product

Elementary analysis of calcined material obtained according to Example10.3 showed 0.026 g of C, less than 0.5 g of N, 0.06 g of Na, 2.4 g ofCu, 3 g of Al and 39.0 g of Si, in each case per 100 g of calcinedmaterial.

The BET surface of the calcined material was 521.9 m²/g, determinedaccording to DIN 66131, and the Langmuir surface area was 700.3 m²/g,determined according to DIN 66135. Typical crystallites had a meanlength of about 1.5-3 micrometers (see FIGS. 40-42).

CE 2 (Example According to Prior Art) Production of a Cu ContainingZeolitic Material Having CHA Framework Structure Via Ion Exchange

CE 2.1 Preparation of the Synthesis Gel

The following starting materials were employed:

-   -   Trimethyl-1-adamantylammonium hydroxide (TMAA, 13.4 wt.-% in        water, Sachen Lot. A7089OX16007)    -   Sodium hydroxide (NaOH pellets, >99% Riedel-de Haen)    -   Aluminum triisopropylate (Aldrich 22,041-8, Lot. S42369-457)    -   Ludox AS40

In a 3 L plastic beaker, 805.6 g of TMAA and 28.1 g of NaOH were mixed.This solution was stirred for 10 min at room temperature. Then, 114.7 gof Aluminum triisopropylate were added, and the resulting suspension wasstirred for about 60 min. Subsequently, 1051.6 g Ludox AS40 were added,and the resulting suspension was stirred for about 20 min.

The pH of the obtained suspension was 13.5.

The suspension had a composition with the following molar ratios: 36SiO₂:2.8 Al isprop.:2.6 TMAA:3.6 NaOH:379H₂O. This gel was transferredin to a 2.5 liter autoclave.

CE 2.2 Hydrothermal Crystallization

The autoclave was sealed and heated to a temperature of 170° C. Thetemperature of 170° C. was maintained for 40 h. Thereby, the mixture ina 2.5 L autoclave was stirred at 200 rpm (revolutions/minute).

CE 2.3 Separation, Drying, and Calcination

After the hydrothermal crystallization, the resulting suspension had apH of 11.95. This suspension was admixed (1:1) with deionized water, andthe pH of the resulting suspension was adjusted to 7.5 with 5% HNO₃.Then, the suspension was filtrated with a porcelain suction filter witha diameter of 15 cm. The wet product was then spray dried (cyclontemperature was 130° C. and drying gases temperature was 300° C.). Thedried product was then calcined in a rotary kiln at a temperature of600° C. to remove the template and ensure a C content less than 0.1 wt%. A sample of the calcined material was examined via XRD, and it wasfound that a zeolite having CHA framework had been obtained (see FIG.43).

CE 2.4 Characterization of the Product

Elementary analysis of calcined material obtained according to CE 2.3showed 0.068 g of C, less than 0.5 g of N, less than 0.78 g of Na, 2.9 gof Al and 38.0 g of Si, in each case per 100 g of calcined material.This correlates to a SiO₂:Al₂O₃ ratio of 25.2.

CE 2.5 Ammonium Exchange of Na-Form

A NH₄-chabazite powder catalyst was prepared by ion-exchange withammonium nitrate. An ammonium nitrate solution was prepared by mixing22.5 g of the ammonium nitrate with 2.25 L of deionized water at 60° C.450 g of Na-form chabazite from CE 2.3 was then added to this solution.An ion-exchange reaction between the Na⁺-form chabazite and the ammoniumions was carried out by agitating the slurry at 60° C. for 1 hour. Theresulting mixture was then filtered, washed until the filtrate had aconductivity of <200 μScm⁻¹, which indicated that substantially nosoluble or free copper remained in the sample, and the washed sample wasdried at 90° C.

Elementary analysis of the material obtained showed 0.54 g of NH₄ andless than 0.01 g of Na per 100 g of material.

CE 2.6 Copper Exchange of NH₄-Form

A Cu chabazite powder catalyst was prepared by ion-exchange with copperacetate. A 0.1 M copper (II) acetate monohydrate solution was preparedby dissolving 16 g of the copper salt in 800 ml of deionized water at60° C. 200 g of NH₄ ⁺-form chabazite according to CE 2.5 was then addedto this solution. An ion-exchange reaction between the NH4⁺-formchabazite and the copper ions was carried out by agitating the slurry at60° C. for 1 hour. The pH was between 4.8 and 4.6 during the reaction.The resulting mixture was then filtered, washed until the filtrate had aconductivity of <200 μScm⁻¹, which indicated that substantially nosoluble or free copper remained in the sample, and the washed sample wasdried at 90° C.

Elementary analysis of the material obtained according to 1.3 showed0.068 g of C, less than 0.5 g of N, less than 0.01 g of Na, 1.6 g of Cu,2.6 g of Al and 35.0 g of Si, in each case per 100 g material. Thiscorrelates to a SiO₂:Al₂O₃ ratio of 25.9.

CE 2.7 SCR Test of Sample According to CE 2.6

CE 2.7.1 Preparation of a Slurry

150 g of the zeolitic material containing Cu and having CHA frameworkstructure, obtained according to CE 2.6 was mixed with 358 ml ofdeionized water. The mixture was ball-milled for 11 hours to obtain aslurry which comprised 90% particles smaller than 10 micrometer. 26 g ofzirconium acetate in dilute acetic acid (containing 30% ZrO₂) were addedto the slurry with agitation

CE 2.7.2 Coating

The slurry was coated onto 1″D×3″L cellular ceramic cores having a celldensity of 65 cpsc (cells per square cm) (400 cpsi (cells per squareinch)) and a wall thickness of 6.5 mm. The coated cores were dried at110° C. for 3 hours and calcined at 400° C. for 1 hour. The coatingprocess was repeated once to obtain a target washcoat loading of 0.146g/cm³ (2.4 g/in³). The washcoat loading is defined as the dry weightgain on the honeycomb with respect to volume.

CE 2.7.3 Measuring NOx Selective Catalytic Reduction (SCR) Efficiency

Nitrogen oxides selective catalytic reduction (SCR) efficiency andselectivity of a fresh catalyst core according to 2.7.2 were measured byadding a feed gas mixture of 500 ppm of NO, 500 ppm of NH₃, 10% O₂, 5%H₂O, balanced with N₂ to a steady state reactor containing a 1″D×3″Lcatalyst core.

For the catalytic test, the washcoated core was shaped into a squarecross section wrapped with a ceramic insulation mat and placed inside anInconel reactor tube heated by an electrical furnace. The gases, O₂(from air), N₂ and H₂O were preheated in a preheater furnace beforeentering the reactor. The reactive gases NO and NH₃ were introducedbetween the preheater furnace and the reactor.

The reaction was carried at a space velocity of 80,000 h⁻¹ across a 150°C. to 460° C. temperature range. Space velocity is defined as the gasflow rate comprising the entire reaction mixture divided by thegeometric volume of the catalyst core. These conditions define thestandard test for fresh catalysts.

FIG. 44 shows the results of the SCR test, indicating the catalyticefficiency and selectivity of the fresh catalyst.

CE 2.7.4 Measuring Hydrothermal Stability of the Catalyst

Hydrothermal stability of the catalyst was measured by hydrothermalaging of the fresh catalyst core described above under section CE 2.7.2in the presence of 10 wt.-% H₂O at 850° C. for 6 hours, followed bymeasurement of the nitrogen oxides SCR efficiency and selectivity by thesame process, as outlined above under section CE 2.7.3, for the SCRevaluation on a fresh catalyst core.

The results of the SCR efficiency and selectivity of the aged catalystis depicted in FIG. 45.

SHORT DESCRIPTION OF THE FIGURES

FIG. 1 shows the XRD pattern of the calcined zeolitic material havingCHA framework type according to Example 1. The powder X-ray diffractionpatterns were recorded on a Siemens D-5000 with monochromatic Cu Kalpha-1 radiation, a capillary sample holder being used in order toavoid a preferred orientation. The diffraction data were collected usinga position-sensitive detector from Braun, in the range from 8 to 96° (2theta) and with a step width of 0.0678°. Indexing of the powder diagramwas effected using the program Treor90, implemented in powder-X (Treor90is a public domain program which is freely accessible via the URLhttp://www.ch.iucr.org/sincris-top/logiciel/). In the figure, the angle2 theta in ° is shown along the abscissa and the intensities (LC=LinCounts) are plotted along the ordinate.

FIG. 2 shows a typical crystallite of the calcined zeolitic materialhaving CHA framework type according to Example 1, determined by SEM(Fig. with secondary electrons 5 kV; scale 20000:1).

FIG. 3 shows the increase of the degree of crystallinity of the calcinedsamples obtained according to Example 2.

FIG. 4 shows the XRD pattern of the calcined product having CHAframework type, obtained according to Example 2 after a totalcrystallization time of 92 h. As to the method of determining the XRDpattern, see FIG. 1.

FIG. 5 shows the XRD pattern of the calcined sample S1 obtainedaccording to Example 3. As to the method of determining the XRD pattern,see FIG. 1.

FIG. 6 shows the XRD pattern of the calcined sample S2 obtainedaccording to Example 3, having CHA framework type. As to the method ofdetermining the XRD pattern, see FIG. 1.

FIG. 7 shows the XRD pattern of the calcined sample S3 obtainedaccording to Example 3, having CHA framework type. As to the method ofdetermining the XRD pattern, see FIG. 1.

FIG. 8 shows schematically the apparatus used for spray-drying thesamples according to Example 3. The reference signs (a)-(k) have thefollowing meaning:

-   -   (a) spay-drier    -   (b) vessel containing the sample to be subjected to spray-drying    -   (c) pump    -   (d) atomizing gas (spray gas)    -   (e) electric heating    -   (f) drying gas    -   (g) atomizer    -   (h) cyclone    -   (i) off-gas    -   (k) spray-dried product

FIG. 9 shows the XRD pattern of the calcined sample S4 obtainedaccording to Example 3, having CHA framework type. As to the method ofdetermining the XRD pattern, see FIG. 1.

FIG. 10 shows crystallites of the calcined zeolitic material S4 havingCHA framework type according to Example 3, determined by SEM (Fig. withsecondary electrons 5 kV; scale: 200:1).

FIG. 11 shows crystallites of the calcined zeolitic material S4 havingCHA framework type according to Example 3, determined by SEM (Fig. withsecondary electrons 5 kV; scale: 1000:1).

FIG. 12 shows crystallites of the calcined zeolitic material S4 havingCHA framework type according to Example 3, determined by SEM (Fig. withsecondary electrons 5 kV; scale: 5000:1).

FIG. 13 shows crystallites of the calcined zeolitic material S4 havingCHA framework type according to Example 3, determined by SEM (Fig. withsecondary electrons 5 kV; scale: 20000:1).

FIG. 14 shows the XRD pattern of the calcined sample S5 obtainedaccording to Example 3, having CHA framework type. As to the method ofdetermining the XRD pattern, see FIG. 1.

FIG. 15 shows crystallites of the calcined zeolitic material S5 havingCHA framework type according to Example 3, determined by SEM (Fig. withsecondary electrons 5 kV; scale: 200:1).

FIG. 16 shows crystallites of the calcined zeolitic material S5 havingCHA framework type according to Example 3, determined by SEM (Fig. withsecondary electrons 5 kV; scale: 1000:1).

FIG. 17 shows crystallites of the calcined zeolitic material S5 havingCHA framework type according to Example 3, determined by SEM (Fig. withsecondary electrons 5 kV; scale: 5000:1).

FIG. 18 shows crystallites of the calcined zeolitic material S5 havingCHA framework type according to Example 3, determined by SEM (Fig. withsecondary electrons 5 kV; scale: 20000:1).

FIG. 19 shows the result of an SCR test of sample S5 applied onto acellular ceramic core according to Example 4 (fresh SCR catalyst).Abbreviation “T” stand for the inlet temperature in ° C., abbreviation“%” for the conversion of NOx, NH₃. Abbreviation “ppm” stands for N₂Omake. The symbols of the curves represent the following chemicalcompounds:

-   -   ♦ NOx (conversion)    -   ▪ NH₃ (conversion)    -   ▴ N₂O (production)

FIG. 20 shows the result of an SCR test of sample S5 applied onto acellular ceramic core according to Example 4 (aged SCR catalyst).Abbreviation “T” stand for the inlet temperature in ° C., abbreviation“%” for the conversion of NOx, NH₃. Abbreviation “ppm” stands for N₂Omake. The symbols of the curves represent the following chemicalcompounds:

-   -   ♦ NOx (conversion)    -   ▪ NH₃ (conversion)    -   ▴ N₂O (production)

FIG. 21 shows the XRD pattern of the Cu and La containing calcinedzeolitic material having CHA framework type according to Example 5. Asto the method of determining the XRD pattern, see FIG. 1.

FIG. 22 shows crystallites of the Cu and La containing calcined zeoliticmaterial having CHA framework type according to Example 5, determined bySEM (Fig. with secondary electrons 5 kV; scale: 1000:1).

FIG. 23 shows crystallites of the Cu and La containing calcined zeoliticmaterial having CHA framework type according to Example 5, determined bySEM (Fig. with secondary electrons 5 kV; scale: 5000:1).

FIG. 24 shows crystallites of the Cu and La containing calcined zeoliticmaterial having CHA framework type according to Example 5, determined bySEM (Fig. with secondary electrons 5 kV; scale: 20000:1).

FIG. 25 shows the XRD pattern of the Cu containing calcined zeoliticmaterial having CHA framework type according to Example 6. As to themethod of determining the XRD pattern, see FIG. 1.

FIG. 26 shows crystallites of the Cu containing calcined zeoliticmaterial having CHA framework type according to Example 6, determined bySEM (Fig. with secondary electrons 5 kV; scale: 1000:1).

FIG. 27 shows crystallites of the Cu containing calcined zeoliticmaterial having CHA framework type according to Example 6, determined bySEM (Fig. with secondary electrons 5 kV; scale: 5000:1).

FIG. 28 shows crystallites of the Cu containing calcined zeoliticmaterial having CHA framework type according to Example 6, determined bySEM (Fig. with secondary electrons 5 kV; scale: 20000:1).

FIG. 29 shows the result of an SCR test of the material obtainedaccording to example 6 applied onto a cellular ceramic core according toexample 7 (fresh SCR). Abbreviation “T” stand for the inlet temperaturein ° C., abbreviation “%” for the conversion of NOx, and NH₃.Abbreviation “ppm” stands for N₂O make. The symbols of the curvesrepresent the following chemical compounds:

-   -   ♦ NOx (conversion)    -   ▪ NH₃ (conversion)    -   ▴ N₂O (production)

FIG. 30 shows the result of an SCR test of the material obtainedaccording to example 6 applied onto a cellular ceramic core according toexample 7 (aged SCR). Abbreviation “T” stand for the inlet temperaturein ° C., abbreviation “%” for the conversion of NOx, and NH₃.Abbreviation “ppm” stands for N₂O make. The symbols of the curvesrepresent the following chemical compounds:

-   -   ♦ NOx (conversion)    -   ▪ NH₃ (conversion)    -   ▴ N₂O (production)

FIG. 31 shows the result of an SCR test of the material obtainedaccording to example CE 1.3.1 according to prior art applied onto acellular ceramic core according to CE 1.3.2 (fresh SCR catalyst CE1.3.3). Abbreviation “T” stand for the inlet temperature in ° C.,abbreviation “%” for the conversion of NOx and NH₃. Abbreviation “ppm”for N₂O make. The symbols of the curves represent the following chemicalcompounds:

-   -   ♦ NOx (conversion)    -   ▪ NH₃ (conversion)    -   ▴ N₂O (production)

FIG. 32 shows the result of an SCR test of the material obtainedaccording to example CE 1.3.1 according to prior art applied onto acellular ceramic core according to CE 1.3.2 (aged SCR catalyst CE1.3.4). Abbreviation “T” stand for the inlet temperature in ° C.,abbreviation “%” for the conversion of NOx and NH₃. Abbreviation “ppm”for N₂O make. The symbols of the curves represent the following chemicalcompounds:

-   -   ♦ NOx (conversion)    -   ▪ NH₃ (conversion)    -   ▴ N₂O (production)

FIG. 33 shows the XRD pattern of the Cu containing calcined zeoliticmaterial having CHA framework type according to Example 8 after 48 hrscrystallization time. As to the method of determining the XRD pattern,see description of FIG. 1 above.

FIG. 34 shows crystallites of the Cu containing calcined zeoliticmaterial having CHA framework type according to Example 8 after 48 hrscrystallization time, determined by SEM (Fig. with secondary electrons 5kV; scale: 1000:1).

FIG. 35 shows crystallites of the Cu containing calcined zeoliticmaterial having CHA framework type according to Example 8 after 48 hrscrystallization time, determined by SEM (Fig. with secondary electrons 5kV; scale: 5000:1).

FIG. 36 shows crystallites of the Cu containing calcined zeoliticmaterial having CHA framework type according to Example 8 after 48 hrscrystallization time, determined by SEM (Fig. with secondary electrons 5kV; scale: 20000:1).

FIG. 37 shows the result of an SCR test of the material obtainedaccording to Example 8 applied onto a cellular ceramic core according toexample 9 (fresh SCR). Abbreviation “T” stand for the inlet temperaturein ° C., abbreviation “%” for the conversion of NOx, and NH₃.Abbreviation “ppm” for N₂O make. The symbols of the curves represent thefollowing chemical compounds:

-   -   ♦ NOx (conversion)    -   ▪ NH₃ (conversion)    -   ▴ N₂O (production)

FIG. 38 shows the result of an SCR test of the material obtainedaccording to Example 8 applied onto a cellular ceramic core according toexample 9 (aged SCR). Abbreviation “T” stand for the inlet temperaturein ° C., abbreviation “%” for the conversion of NOx, and NH₃.Abbreviation “ppm” for N₂O make. The symbols of the curves represent thefollowing chemical compounds

-   -   ♦ NOx (conversion)    -   ▪ NH₃ (conversion)    -   ▴ N₂O (production)

FIG. 39 shows the XRD pattern of the Cu containing calcined zeoliticmaterial having CHA framework type according to Example 10 after 48 hrscrystallization time. As to the method of determining the XRD pattern,see description of FIG. 1 above.

FIG. 40 shows crystallites of the Cu containing calcined zeoliticmaterial having CHA framework type according to Example 10 after 48 hrscrystallization time, determined by SEM (Fig. with secondary electrons 5kV; scale: 1000:1).

FIG. 41 shows crystallites of the Cu containing calcined zeoliticmaterial having CHA framework type according to Example 10 after 48 hrscrystallization time, determined by SEM (Fig. with secondary electrons 5kV; scale: 5000:1).

FIG. 42 shows crystallites of the Cu containing calcined zeoliticmaterial having CHA framework type according to Example 10 after 48 hrscrystallization time, determined by SEM (Fig. with secondary electrons 5kV; scale: 20000:1).

FIG. 43 shows the XRD pattern of the Cu containing calcined zeoliticmaterial having CHA framework type according to comparative example CE 2after 40 hrs crystallization time. As to the method of determining theXRD pattern, see description of FIG. 1 above.

FIG. 44 shows the result of an SCR test of the material obtainedaccording to comparative example CE 2 applied onto a cellular ceramiccore according to comparative example CE 2.7.3 (fresh SCR). Abbreviation“T” stand for the inlet temperature in ° C., abbreviation “%” for theconversion of NOx, and NH₃. Abbreviation “ppm” for N₂O make. The symbolsof the curves represent the following chemical compounds:

-   -   ♦ NOx (conversion)    -   ▪ NH₃ (conversion)    -   ▴ N₂O (production)

FIG. 45 shows the result of an SCR test of the material obtainedaccording to comparative example CE 2 applied onto a cellular ceramiccore according to comparative example 2.7.4 (aged SCR). Abbreviation “T”stand for the inlet temperature in ° C., abbreviation “%” for theconversion of NOx, and NH₃. Abbreviation “ppm” for N₂O make. The symbolsof the curves represent the following chemical compounds

-   -   ♦ NOx (conversion)    -   ▪ NH₃ (conversion)    -   ▴ N₂O (production)

The invention claimed is:
 1. A process for preparing a copper-containingzeolitic material having a CHA framework structure, the processcomprising: (i) preparing an aqueous solution comprising at least onesource for X₂O₃, at least one source for YO₂, at least one structuredirecting agent suitable for preparing a zeolitic material having a CHAframework structure, and at least one Cu source, wherein said aqueoussolution does not comprise a phosphor source and has an alkali metalcontent of 1000 ppm or less; and (ii) hydrothermally crystallizing theaqueous solution of the preparing (i) which does not comprise a phosphorsource, to obtain a suspension comprising the copper-containing zeoliticmaterial having a CHA framework structure; wherein the structuredirecting agent is a mixture of 1-adamantyltrimethyl-ammonium hydroxideand benzyltrimethylammonium hydroxide, or a mixture of1-adamantyltrimethylammonium hydroxide and tetramethylammoniumhydroxide, or a mixture of 1-adamantyltrimethylammonium hydroxide andtetramethylammonium hydroxide, or a mixture of1-adamantyltrimethylammonium hydroxide and benzyltrimethylammoniumhydroxide and tetramethylammonium hydroxide, wherein a molar ratio of1-adamantyltrimethylammonium hydroxide to benzyltrimethylammoniumhydroxide or to tetramethylammonium hydroxide, or to a sum ofbenzyltrimethylammonium hydroxide and tetramethylammonium hydroxide, isin a range of from 1:5 to 1:1, and wherein the copper-containingzeolitic material has a composition comprising a molar ratio(nYO₂):X₂O₃ wherein X is a trivalent element, Y is a tetravalentelement, and n is at least
 10. 2. The process of claim 1, wherein X isat least one selected from the group consisting of AI, B, In, and Ga,and wherein Y is at least one selected from the group consisting of Si,Sn, Ti, Zr, and Ge.
 3. The process of claim 2, wherein X is Al and Y isSi.
 4. The process of claim 1, wherein an aqueous solution comprising Cuand ammonia is employed as a Cu source.
 5. The process of claim 1,wherein, for the preparing (i), the at least one source for YO_(Z), theat least one source for X_(Z)0₃, and the at least one Cu source areemployed in such amounts that the aqueous solution obtained according to(i) exhibits a molar ratio(nYO₂):X₂O₃ wherein n is at least 10, and a molar ratio(mCu):((nYO₂)+X₂O₃) wherein m is at least 0.005.
 6. The process of claim1, wherein the pH of the aqueous solution subjected to thehydrothermally crystallizing (ii) is in a range of from 12 to
 14. 7. Theprocess of claim 1, wherein the hydrothermally crystallizing (ii) iscarried out at a temperature in a range of from 100 to 200° C. and for atime period of from 12 to 144 h.
 8. The process of claim 1, wherein theaqueous solution subjected to the hydrothermally crystallizing (ii)comprises a La source.
 9. The process of claim 1, further comprising(iii) separating the copper-containing zeolitic material from thesuspension obtained in the hydrothermally crystallizing (ii); (iv)drying the copper-containing zeolitic material, separated in (iii), at atemperature in a range of from 100 to 150° C.; and (v) calcining thecopper-containing zeolitic material, dried in (iv), at a temperature ina range of from 300 to 600° C.
 10. The process of claim 1, wherein,after the preparing (i), no Cu source is employed.
 11. Acopper-containing zeolitic material having framework structure CHA,obtained by the process of claim 1.